JPH11108816A - Resin tensile tester - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin tensile test device having a wide speed range from low speed to high speed and capable of applying a tensile load at a constant speed excluding a speed change region immediately after start of startup. A pedestal (3) erected through a plurality of column bases (2) and having a horizontal flat plate (3a) at an upper portion, and a top plate (14) vertically erected on the flat plate of the pedestal and formed of a horizontal flat plate on a top. Linear actuator 10 comprising a ball screw mechanism,
A rotary motor penetrates the flat plate, is connected to the linear motion actuator, and is fixed to the lower side of the flat plate for driving the linear motion actuator; and a ball screw protruded from the movable portion of the linear motion actuator. It comprises a crosshead 16 which can be moved up and down by a mechanism, and a pair of upper and lower clamps 40 and 50 which are disposed between the crosshead and the gantry plate and respectively hold the ends of the resin tensile test pieces.

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. It is possible to apply a load at a much higher speed than the tensile test equipment for the test, and to carry out the stress relaxation test and the recovery test after the tensile test, so that the exact mechanical properties of the resin can be quickly grasped. The present invention relates to a tensile test device for resin intended to do so.

[0002]

2. Description of the Related Art In general, a resin material exhibits viscoelastic viscoplastic characteristics having an effect of viscosity in both an elastic region and a plastic region. Therefore, the speed of a cross head, which is a movable portion of a tensile tester, is varied. A tensile test is required. However, in a test apparatus having a current general rotary screw mechanism, a test speed range necessary for a test for a resin is not considered.

In a test apparatus having a general rotary screw mechanism, one of test piece grippers (also called a clamp) for mounting a test piece is fixed, and the other test piece gripper is pulled to stop at a maximum displacement position. Thus, data on 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 the tensile test speed is at the start of pulling (at the time of rising of data).
In this case, since the speed of the crosshead rises from 0 and settles at a constant speed, an accurate test at a constant speed cannot be performed. FIG. 10 shows the experimental results (load-time characteristics) obtained using a test device having a conventional rotary screw mechanism. At the start of data, the speed becomes constant due to the acceleration of the crosshead. Not. At this time, the crosshead speed that has reached a certain speed is 200 mm / mi.
n. Further, such a conventional test apparatus cannot perform a strain recovery test continuously.

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

[0006]

In order to solve the above-mentioned problems, a first aspect of the present invention relates to a resin for measuring mechanical properties such as tensile strength and stress-strain characteristics of the resin. A tensile test apparatus, comprising a pedestal having a horizontal flat plate at the top and erected through a plurality of column bases, and a top plate vertically erected on the flat plate of the pedestal and made of a horizontal flat plate at the top. Linear actuator consisting of a ball screw mechanism,
A rotating shaft penetrating through the flat plate and connected to the linear actuator, a servomotor for driving the linear actuator fixed below the flat plate, and protruding from a movable portion of the linear actuator; A cross head that can be moved up and down by a ball screw mechanism, and a pair of upper and lower clamps that are disposed between the cross head and the gantry flat plate and grip an end of a resin tensile test piece, respectively. An upper clamp is vertically erected along the direct-acting type actuator via a load sensor on the gantry flat plate, and the upper clamp penetrates vertically through a through hole formed in the crosshead and is larger than the inner diameter of the through hole at the upper end. A guide rod having a stopper having a diameter is hung on a guide weight having the same weight as that of the upper clamp through a pulley provided at a lower portion of the top plate. It was ligated to each other via the de.

According to a second aspect of the present invention, in the first aspect, a linear ball bearing is disposed in a through hole of the crosshead in which the guide rod moves up and down.

Further, in the third invention, in the first and second inventions, the clamp is joined with the pin while surrounding the pair of left and right pressure pads with the quadrilateral link, and the operation of the quadrilateral link is performed. The link was urged in the direction of holding the resin test piece between the two pressing pads via a tension coil spring.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the first aspect of the present invention, there is provided a gantry having a horizontal flat plate on an upper portion thereof, which is erected through a plurality of column bases, and is vertically erected on the flat plate of the gantry. A direct-acting actuator comprising a ball screw mechanism having a top plate made of a horizontal flat plate at the top, and a rotary shaft penetrating through 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 linear actuator, a crosshead protruding from a movable portion of the linear actuator and capable of moving up and down by a ball screw mechanism, and a resin disposed between the crosshead and the base plate. A pair of upper and lower clamps for gripping the end of the tensile test piece, a lower clamp is erected on the gantry flat plate along the linear actuator via a load sensor, and an upper clamp is Is vertically suspended through a through-hole pierced through a guide rod provided with a stopper having a diameter larger than the inner diameter of the through-hole at the upper end, and the stopper is provided at a lower portion of the top plate. The weight of the upper clamp is the same as the weight of the upper clamp, and 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 ends of the tensile test piece for resin are gripped by both clamps, the tensile test can be started in a state in which the weight of the upper clamp is not loaded on the tensile test piece for resin, and a desired high-speed crosshead speed can be obtained. Can apply a load to the tensile test piece for resin.

According to the second aspect of the present invention, since the linear ball bearing is provided 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. And accurate vertical up and down movement can be ensured by eliminating lateral vibration.

Further, in the third aspect of the present invention, the clamp includes a pair of right and left pressing pads surrounded by a quadrilateral link and is joined by pins, and an operation link of the quadrilateral link is pulled through a tension coil spring. As it was made to urge in the direction to pinch the resin test piece with the two pressure pads,
With one touch, the tensile test specimen for resin can be quickly attached to and detached from a pair of left and right clamps.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The 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,
1 is an overall perspective view of a tensile tester for resin, FIG. 2 is a side view of a main part of the tensile tester for resin, FIG. 3 is a front view of a clamp,
FIG. 4 is a perspective view of a clamp showing another embodiment, and FIG.
FIG. 6 is a graph showing the test results (load-time characteristics) of the resin tensile tester of the present invention, and FIG. 7 is the test results (load-time characteristics) of the resin tensile tester of the present invention. FIG. 8 is a graph showing test results (displacement-time characteristics) of the resin tensile test device of the present invention, and FIG. 9 is a test result (stress-strain characteristics) of the resin tensile test device of the present invention. It is a graph. FIG. 10 is a graph showing test results (load-time characteristics) of a conventional commercial testing machine.

FIG. 1 shows a resin tensile test apparatus 10 according to the present invention.
0, the resin tensile test apparatus 100 is shown in FIG.
As shown in FIG. 2 and FIG. 2, a gantry 3 erected on a horizontal bottom plate 1 by four column bases 2 and provided with a gantry flat plate 3a on an upper portion, and a gantry 3 vertically erected on the gantry flat plate 3a. Linear actuator 10 comprising a ball screw mechanism provided with a top plate 14 comprising a horizontal flat plate, and a rotating shaft 20a penetrating the base plate 3a and connected to the linear actuator 10 to be fixed below the base plate 3a. A servomotor 20 for driving the linear actuator provided, a crosshead 16 protruding from a movable portion of the linear actuator 10 and movable up and down by a ball screw mechanism, and between the crosshead 16 and the flat base plate 3a. It is provided with a pair of upper and lower lower clamps 40 and upper clamps 50 which are disposed and respectively hold the ends of the resin tensile test pieces TP.

The lower clamp 40 is erected and fixed to the gantry flat plate 3a along the direct-acting actuator 10 via the load sensor 30, while the upper clamp 50 is penetrated vertically through the crosshead 16. The guide hole 52 has a stopper 54 having a diameter larger than the inner diameter of the through hole 16a. The stopper 54 is disposed below the top plate 14. The pulley 58 is connected to a weight 60 having the same weight as the upper clamp 50 via a cord 56. The weight of the crosshead 16 is set to be larger than the weight of the upper clamp 50. Load sensor 30
For example, a commercially available load cell, magnecell, or the like may be used, or other known sensors 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 inside 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 details of the clamps 40 and 50 (the upper clamp 50 is an inverted top of FIG. 3) for gripping both ends of a cylindrical resin tensile test piece TP, respectively. The clamp 40 composed of a partially cut-out block is also provided with two pads 4 symmetrically in the upper central space.
0a, 40b are arranged so as to face each other, and a screw rod 42 in which a screw hole provided in the clamp 40 is screwed.
Is disposed so as to be able to move forward and backward in the horizontal direction by the rotation of the lever 42a. The ends of the resin tensile test piece TP are sandwiched between the pads 40a and 40b so that the resin tensile test piece TP can be attached or detached. It was done.

4 and 5 show clamps 40,
Fifth embodiment is shown, corresponding 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 within a clamp 40 having a box-shaped square frame. A pair of left and right pads 40a and 40b each having a curved surface whose opposite surface is an arc corresponding to the diameter of the resin tensile test piece TP is pin-joined to the inside of 44, and an operation link bent into an L-shape which is one of the links 44a. One end of the extension coil 44b projects outside the cutout portion of the frame of the clamp 40,
Urges both pads in the approaching direction.
Therefore, when mounting the resin tensile test piece TP, the operation link 44b is pushed up in the direction F (upward direction in FIG. 5) shown in FIG.
When the user releases the hand after setting one end of the resin tensile test piece TP between 40b, one end of the resin tensile test piece TP is firmly gripped by the clamp 40 by the spring force of the tensile coil spring 45. In the present embodiment, the embodiment of FIG. 3 takes a long time in the screwing operation of the pair of left and right screw rods 42, 42, and it takes much time to set the resin tensile test piece TP at the center position of the clamps 40, 50. On the other hand, when it can be attached and detached with one touch and the diameter of the resin tensile test piece TP is constant, it can be surely set to the center position of the clamps 40 and 50 every time.

In the resin tensile test apparatus 100 of the present invention configured as described above, the resin tensile test piece TP is gripped at both ends by a pair of upper and lower clamps 40 and 50,
When the servomotor 20 is driven to move the crosshead 16 upward, there is some gap between the upper surface of the crosshead 16 and the lower surface of the stopper 54, so that the upper clamp 50 remains stationary and the upper surface of the crosshead 16 Stopper 5
Since the upper clamp 50 starts to move from the moment when the lower head 4 reaches the lower surface and the two heads come into contact with each other, the crosshead 16 reaches a certain speed regardless of the initial speed at which the crosshead 16 starts operating.
Can be transmitted to the upper clamp 50, that is, the resin tensile test piece TP. That is, the above-mentioned gap is a run-up section for starting the crosshead 16. Furthermore, since it is used in conjunction with the servomotor 20 and the linear actuator 10 having a ball screw mechanism, a wide range of crosshead speeds (1 to 10000 mm / min) from a low speed to an arbitrary high speed can be obtained with certainty. A high tensile test is performed. Also, as described above, the weight of the crosshead 16 is
, The speed drop that occurs when the upper surface of the crosshead 16 abuts against the lower surface of the stopper 54 can be slightly suppressed.

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

FIG. 7 (load-time characteristics) and FIG. 8 (displacement-time characteristics) show the results of tests performed using the resin tensile test apparatus 100 of the present invention. It is shown that. FIG. 9 shows the stress-strain characteristics obtained from the measurement results.
This is an example in which four types are changed every 10 times from mm / min. It shows that a series of tests can be performed continuously from tension to stress relaxation and strain recovery with a wide speed range.

[0021]

As described above, according to the present invention,
In addition to being able to perform tensile tests over a wide speed range that is far beyond the speed range that can be achieved with a test device having a conventional rotary screw mechanism, the crosshead speed at the start of tension is kept constant,
Since the stress relaxation test can be continuously performed by fixing the crosshead after the tensile test, and the strain recovery test can be continuously performed by returning the crosshead, it 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 in order to obtain the constitutive equation more accurately.

[Brief description of the drawings]

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

FIG. 2 is a side view of a main part of a tensile tester for resin 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.

FIG. 5 is a plan view of the clamp of FIG. 4;

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

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

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

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

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Bottom plate 2 Column base 3 Stand 3a Stand flat plate 10 Direct-acting actuator 12 Stand 14 Top plate 16 Crosshead 20 Servomotor 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 Weight 100 Resin tensile tester TP Resin tensile test piece

Claims (3)

[Claims] 1. A resin tensile tester for measuring mechanical properties such as tensile strength and stress-strain characteristics of a resin, comprising: And a linear motion actuator comprising a ball screw mechanism having a top plate formed of a horizontal flat plate on the top of the mount, and a rotating shaft penetrates the flat plate and the linear motion actuator. A servomotor for driving the linear actuator connected and fixed below the flat plate, a crosshead protruding 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 respectively disposed between the frame and the gantry plate and gripping the ends of the resin tensile test pieces, and a lower clamp is provided with a load sensor along the linear motion type actuator on the gantry plate. The upper clamp is vertically pierced through a through hole formed in the crosshead, and is suspended by a guide rod having a stopper having a diameter larger than the inner diameter of the through hole at the upper end. A 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 at a 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 provided in a through hole of the crosshead in which the guide rod moves up and down. 3. The clamp includes a pair of left and right pressing pads surrounded by a quadrilateral link and is joined by pins, and an operation link of the quadrilateral link is pulled by a resin coil between the two pressing pads via a coil spring. The resin tensile test apparatus according to claim 1, wherein the resin test piece is urged in a direction to clamp the test piece.