JP3518279B2 - Resin tensile tester - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin tensile tester for measuring mechanical properties such as tensile strength, stress-strain characteristics, and elastic modulus of various industrial or medical resins, and more particularly to conventional resin The load can be applied at a much higher speed than the tensile test equipment for use, and the stress relaxation test and the recovery test can be continuously performed after the tensile test to quickly grasp the accurate mechanical properties of the resin. The present invention relates to a tensile test device for a resin intended to do so.

[0002]

2. Description of the Related Art In general, resin materials exhibit viscoelastic viscoplasticity characteristics that have the effect of viscosity in both elastic and plastic regions. Therefore, the speed of the crosshead, which is the movable part of the tensile tester, was variously changed. Tensile test is required. However, the current test apparatus having a general rotary screw mechanism does not consider the test speed range required for the resin test.

In a test apparatus having a general rotary screw mechanism, one of the test piece gripping tools (also referred to as clamps) on which the test piece is mounted is fixed, and the other test piece gripping tool is pulled and stopped at the maximum displacement position. Thus, the data of the correlation between the load and the displacement is obtained.

[0004]

However, the tensile test speed is about 1000 mm / min even at a high speed, and at the start of pulling (when the data starts rising).
In, the crosshead speed rises from 0 and settles down to a constant speed, so an accurate test at a constant speed cannot be performed. FIG. 10 shows an experimental result (load-time characteristic) obtained by using a conventional test device having a rotary screw mechanism. The speed becomes constant due to the acceleration of the crosshead when the data rises. Not not. At this time, the crosshead speed that reached the constant speed is 200 mm / mi.
n. In addition, such a conventional test apparatus cannot continuously perform the strain recovery test.

On the other hand, the impact test apparatus capable of performing a tensile test at a higher speed has an excessively low minimum speed, and is unsuitable for a test at a low speed. In addition, even if an experiment using a test device having a rotary screw mechanism and an impact test device is performed together, there is often no consistency between the data from the two test devices.
Moreover, because the structure uses compressed air as the power source, it is not possible to perform a stress relaxation test by fixing the displacement after a tensile test, and a continuous strain recovery test is performed as in the conventional test device with a rotary screw mechanism. I couldn't.

[0006]

In order to solve the above problems, in the present invention, in the first invention, a resin for measuring mechanical properties such as tensile strength and stress-strain characteristic of the resin is used. A tensile tester comprising: a pedestal that is erected via a plurality of column bases and has a horizontal flat plate on the top; and a top plate that is erected vertically on the flat plate of the pedestal and that is a horizontal flat plate on the top Direct-acting actuator consisting of a ball screw mechanism,
A servomotor for driving the direct-acting actuator fixed to the lower side of the flat plate, the rotary shaft penetrating the flat plate and connected to the direct-acting actuator, and a projecting portion on the movable portion of the direct-acting actuator. The cross head is movable up and down by a ball screw mechanism, and a pair of upper and lower clamps are provided between the cross head and the gantry flat plate to grip the ends of the resin tensile test pieces. A pedestal plate is erected along the linear actuator via a load sensor, and an upper clamp vertically penetrates a through hole formed in the crosshead and has an upper end portion having an inner diameter larger than the inner diameter of the through hole. It is suspended by a guide rod having a stopper having a diameter, and the stopper passes through a pulley arranged at the bottom of the top plate and is attached to a weight having the same weight as that of the upper clamp by a cord-shaped cord. It was ligated to each other via the de.

Further, in the second invention, in the first invention, the linear ball bearing is arranged in the through hole of the crosshead in which the guide rod moves up and down.

Further, in the third invention, in the first or second invention, the clamp surrounds the pair of right and left pinching pads with a quadrilateral link while pin-joining them, and operates the quadrilateral link. The link was pulled and biased in the direction in which the resin test piece was held by the two holding pressure pads via a coil spring.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION In the first aspect of the present invention, a pedestal having a horizontal flat plate in an upright position through a plurality of column bases, and a vertical erection on the flat plate of the pedestal. A direct acting actuator consisting of a ball screw mechanism having a top plate made of a horizontal flat plate on the top, and a rotary shaft penetrating the flat plate and connected to the direct acting actuator, and fixed to the lower side of the flat plate. A servomotor for driving a direct-acting actuator, a crosshead projecting from a movable portion of the direct-acting actuator and vertically movable by a ball screw mechanism, and a resin provided between the crosshead and the gantry flat plate, respectively. It consists of a pair of upper and lower clamps that grip the end of the tensile test piece.The lower clamp is erected on the gantry plate along the linear actuator via a load sensor, and the upper clamp is the crosshead. A penetrating hole is vertically movably pierced in a guide rod having a stopper having a diameter larger than the inner diameter of the penetrating hole, and the stopper is arranged at the lower part of the top plate. Since the weight of the upper clamp is connected to the weight having the same weight as that of the upper clamp via the cord, the weight of the upper clamp is equal to the weight of the weight, and the weight of the upper clamp is offset. Therefore, even if both clamps hold both ends of the resin tensile test piece, the tensile test can be started without the weight of the upper clamp being applied to the resin tensile test piece, and the desired high-speed crosshead speed can be achieved. The load can be applied to the tensile test piece for resin.

In the second aspect of the invention, since the linear ball bearing is arranged in the through hole of the crosshead in which the guide rod moves up and down, the guide rod can be moved up and down smoothly with respect to the crosshead. In addition, horizontal shake is eliminated and accurate vertical movement in the vertical direction is secured.

Further, in the third aspect of the invention, in the clamp, the pair of right and left pinching pads are pin-joined while being surrounded by the quadrilateral link, and the operation link of the quadrilateral link is pulled by a coil spring. Since both the pressing pads are urged in the direction of clamping the resin test piece,
The tensile test piece for resin can be quickly attached / detached to / from a pair of left and right clamps with one touch.

[0012]

Embodiments of the present invention will be described below in detail with reference to the drawings. 1 to 9 relate to an embodiment of the present invention,
FIG. 1 is an overall perspective view of the resin tensile test device, FIG. 2 is a side view of a main part of the resin tensile test device, and FIG. 3 is a front view of a clamp.
FIG. 4 is a perspective view of a clamp showing another embodiment, and FIG.
6 is a plan view of the clamp of FIG. 6, FIG. 6 is a graph showing the test results (load-time characteristic) of the resin tensile test device of the present invention, and FIG. 7 is the test result of the resin tensile test device of the present invention (load-time characteristic). 8 is a graph showing the test results (displacement-time characteristics) of the resin tensile test device of the present invention, and FIG. 9 shows the test results (stress-strain property) of the resin tensile test device of the present invention. It is a graph. FIG. 10 is a graph showing the test results (load-time characteristics) of the conventional commercial tester.

FIG. 1 shows a resin tensile test apparatus 10 of the present invention.
0 is shown in FIG.
As shown in FIG. 2 and FIG. 2, a pedestal 3 which is erected by four column bases 2 on a horizontal bottom plate 1 and has a horizontal pedestal plate 3a on the top, and a vertically erected top on the gantry plate 3a A direct-acting actuator 10 including a ball screw mechanism having a horizontal top plate 14 and a rotary shaft 20a penetrating the pedestal plate 3a and connected to the linear-acting actuator 10 are fixed to the lower side of the gantry plate 3a. The servo motor 20 for driving the direct-acting actuator provided, the crosshead 16 projecting from the movable portion of the direct-acting actuator 10 and movable up and down by a ball screw mechanism, and between the crosshead 16 and the gantry flat plate 3a. It is composed of a pair of upper and lower clamps 40 and 50 arranged above and below for gripping the ends of the resin tensile test pieces TP.

The lower clamp 40 is vertically erected and fixed on the gantry plate 3a along the linear actuator 10 via the load sensor 30, while the upper clamp 50 is pierced vertically through the crosshead 16. The penetrating through hole 16a is movably moved up and down, and the upper end portion is suspended by a guide rod 52 having a stopper 54 having a diameter larger than the inner diameter of the through hole 16a. It is connected to the weight 60 having the same weight as the weight of the upper clamp 50 via the cord 58 via the cord 56. The weight of the crosshead 16 is set to be larger than that of the upper clamp 50. Load sensor 30
A commercially available load cell, magnecell, or the like may be used, or any other known sensor may be used.

In order to smooth the vertical movement of the guide rod 52 in the through hole 16a, it is desirable to fit a linear ball bearing having an inner diameter matching the diameter of the guide rod 52 in the through hole 16a ( This corresponds to the second invention of the present invention).

FIG. 3 shows the details of the clamps 40 and 50 (the upper clamp 50 is an upside-down version of FIG. 3) for gripping both ends of the cylindrical resin tensile test piece TP, respectively. The clamp 40, which consists of a block with a part cut away, is also symmetrical to the two pads 4 in the upper central space.
0a, 40b are arranged so as to face each other, and a screw rod 42 screwed into a screw hole provided in the clamp 40.
Is arranged so that it can be moved forward and backward in the horizontal direction by the rotation of the lever 42a, and the ends of the resin tensile test piece TP are sandwiched by both pads 40a and 40b so that the resin tensile test piece TP can be attached or detached. It was done.

On the other hand, FIGS. 4 and 5 show the clamp 40,
Fifty other embodiments are shown and correspond to the third invention of the present invention. This type of clamp 40, 50 is a quadrilateral link formed by seven links 44a flexibly joined by a pin joint in a U-shape in the clamp 40 having a box-shaped frame. A pair of left and right pads 40a, 40b each having a curved surface whose opposing surface is an arc matching the diameter of the resin tensile test piece TP are pin-joined inside 44, and the operation link is bent into an L-shape which is one of the links 44a. One end of 44b is projected to the outside from the cutout portion of the frame body of the clamp 40, and the tension coil spring 45
Thus, both pads are biased toward each other.
Therefore, when mounting the resin tensile test piece TP, the operation link 44b is pushed up in the F direction shown in FIG. 5 (upward direction in FIG. 5) against the spring force, and the expanded pads 40a,
When one end of the resin tensile test piece TP is set between 40b and the hand is released, one end of the resin tensile test piece TP is firmly gripped by the clamp 40 by the spring force of the tension coil spring 45. In this embodiment, the embodiment of FIG. 3 takes a long time for the screwing operation of the pair of left and right screw rods 42, 42, and it is necessary to set the resin tensile test piece TP at the center position of the clamps 40, 50. On the other hand, when the resin tensile test piece TP can be attached and detached with one touch and the diameter of the resin tensile test piece TP is constant, it can be reliably set at the center position of the clamps 40 and 50 every time.

In the resin tensile test apparatus 100 of the present invention constructed as described above, after the resin tensile test piece TP is held at its both ends by the pair of upper and lower clamps 40 and 50,
When the servo motor 20 is driven to move the crosshead 16 upward, the upper clamp 50 remains stationary because the upper surface of the crosshead 16 and the lower surface of the stopper 54 have some gap, and the upper surface of the crosshead 16 is Stopper 5
Since the upper clamp 50 starts to move from the moment when they reach the lower surface of No. 4 and come into contact with each other, the cross head 16 reaches a constant speed regardless of the initial speed at which the cross head 16 starts to operate.
Can be transmitted to the upper clamp 50, that is, the resin tensile test piece TP. That is, the above-mentioned gap is an approach section for starting the crosshead 16. Furthermore, since it is used in conjunction with the servomotor 20 and the direct acting actuator 10 having a ball screw mechanism, a wide range of crosshead speeds (1-10000 mm / min) from low speed to any high speed can be obtained with certainty and accuracy. High tensile test is performed. In addition, as described above, the weight of the crosshead 16 depends on the upper clamp 50.
Since the weight of the crosshead 16 is larger than that of the stopper 54, a decrease in speed that occurs when the upper surface of the crosshead 16 comes into contact with the lower surface of the stopper 54 can be suppressed to a small extent.

The test results obtained by using the resin tensile testing apparatus 100 of the present invention thus constructed will be described. FIG. 6 shows the obtained test results (load-time characteristics). Compared with FIG. 10 of the conventional example, there is almost no change in speed at the start of pulling, although the pulling speed is 50 times faster. I understand.

FIG. 7 (load-time characteristic) and FIG. 8 (displacement-time characteristic) are test results carried out by using the resin tensile testing apparatus 100 of the present invention, and the tests were carried out continuously. It is shown that. FIG. 9 shows the stress-strain characteristics obtained from the measurement results, and the tensile crosshead speed was 10%.
In this example, four types are changed every 10 times from mm / min. It shows that a wide range of speeds and a series of tests from tension to stress relaxation and strain recovery can be performed continuously.

[0021]

As described above, according to the present invention,
Along with being able to perform a tensile test in a wide speed range that far exceeds the speed range that a conventional test device with a rotary screw mechanism can hold, the crosshead speed at the start of tension is held constant,
After the tensile test, the crosshead can be fixed and the stress relaxation test can be continuously performed, and the crosshead can be returned and the strain recovery test can be continuously performed, which is highly convenient and is applied to the finite element method for dynamic stress analysis of resin materials, for example. It is possible to obtain accurate data on the mechanical properties of the resin for obtaining the constitutive equation more accurately.

[Brief description of drawings]

FIG. 1 is an overall perspective view of a resin tensile test device according to an embodiment of the present invention.

FIG. 2 is a side view of a main part of a resin tensile testing device according to an embodiment of the present invention.

FIG. 3 is a front view of the clamp according to the embodiment of the present invention.

FIG. 4 is a perspective view of a clamp according to another embodiment of the present invention.

5 is a plan view of the clamp of FIG.

FIG. 6 is a graph showing test results (load-time characteristics) of the resin tensile test device according to the example of the present invention.

FIG. 7 is a graph showing test results (load-time characteristics) of the resin tensile test device according to the example of the present invention.

FIG. 8 is a graph showing test results (displacement-time characteristics) of the resin tensile test device according to the example of the present invention.

FIG. 9 is a graph showing test results (stress-strain characteristics) of the resin tensile test device according to the example of the present invention.

FIG. 10 is a graph showing test results (load-time characteristics) of a conventional commercial tester.

[Explanation of symbols]

1 bottom plate 2 pillar base 3 mounts 3a Stand flat plate 10 Direct acting actuator 12 stand 14 Top plate 16 crosshead 20 Servo motor 20a rotating shaft 30 load sensor 40 Lower clamp 40a pad 40b bad 42 screw rod 42a lever 44 quadrilateral link 44a link 44b Operation link 45 tension coil spring 50 upper clamp 52 Guide rod 54 Stopper 56 code 60 weights 100 Tensile testing device for resin TP resin tensile test piece

Claims (3)

(57) [Claims] 1. A tensile tester for resin for measuring mechanical properties such as tensile strength and stress-strain characteristic of resin, which is a pedestal having a horizontal flat plate erected upright through a plurality of column bases. And a direct-acting actuator composed of a ball screw mechanism provided vertically on a flat plate of the frame and having a top plate made of a horizontal flat plate at the top, and a rotary shaft passing through the flat plate to provide the direct-acting actuator. A servomotor for driving the linear actuator, which is connected and fixed to the lower side of the flat plate, a crosshead projecting from a movable portion of the linear actuator and vertically movable by a ball screw mechanism, and the crosshead And a pair of upper and lower clamps which are disposed between the base plate and the gantry flat plate and hold the end portions of the resin tensile test pieces, respectively, and the lower clamp includes a load sensor along the linear actuator on the gantry flat plate. And the upper clamp hangs vertically through a through hole formed in the crosshead and hangs down on a guide rod having a stopper at the upper end having a diameter larger than the inner diameter of the through hole. The tensile tester for resin, wherein the stopper is connected to a weight having the same weight as that of the upper clamp through a pulley disposed on the lower portion of the top plate via a cord. 2. The tensile test apparatus for resin according to claim 1, wherein a linear ball bearing is arranged in the through hole of the crosshead in which the guide rod moves up and down. 3. The clamp has a pair of left and right clamping pads surrounded by a quadrilateral link and pin-joined to each other, and an operation link of the quadrilateral link is stretched by a coil spring to form a resin between the clamping pads. The tensile test device for resin according to claim 1 or 2, wherein the tensile test device for resin is urged in a direction in which the test piece for application is clamped.