JPH04361111A - Measuring device of bending displacement - Google Patents

Abstract

PURPOSE:To increase the measuring precision of the data on bending displacement by making measuring conditions unvaried at all times by making support of a sample to be measured stable, when the sample is subjected to bending deformation by a press rod fitted to a robot mechanism part and the relation between a pressing force and the displacement is measured by using a force sensor and a displacement sensor, in particular, in regard to a measuring apparatus of the bending displacement. CONSTITUTION:In a measuring apparatus of bending displacement, a sample 2 to be measured is set on a sample setting stage 10 provided with supporting mechanisms 1 in the opposite ends, the sample 2 is deformed by pressing it by a press rod 3 and the amount of deformation is measured by a displacement sensor. The measuring apparatus of the bending displacement is constructed so that the supporting mechanisms 1 have mechanisms for shifting the support positions of the sample 2 to the direction being perpendicular to a pressing force. Concretely, the shifting mechanism of the supporting mechanism 1 is constructed of a rolling mechanism, for instance.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bending displacement measuring device. Specifically, when the specimen is bent and deformed by a pressing rod attached to the robot mechanism and the relationship between pressing force and displacement is measured using a force sensor and a displacement sensor, the support of the specimen is stabilized. This invention relates to improvements in the support mechanism for a sample to be measured in a bending displacement measuring device, in order to improve the measurement accuracy of bending displacement data by always keeping measurement conditions constant.

0002

2. Description of the Related Art In recent years, there has been a strong demand to reduce the weight of personal computers, word processors, printers, etc., and various plastic molded products have come into widespread use in the field of structural design of housings and the like.

[0003] For this reason, attempts have been made to develop extreme designs that reduce the thickness of these materials and provide the minimum necessary strength. Many of these structures are flexible structures that are easily deformed, and in order to ensure product reliability, it is necessary to ensure sufficient deformation when external forces are applied, such as not only elastic deformation but also plastic deformation and creep deformation. It is necessary to take this into account.

As an apparatus for measuring such bending deformation and strain distribution, there is one already proposed by the present inventors as explained below (Japanese Patent Application No. 02-16687).
(see 7).

FIG. 4 is a diagram showing an example of the configuration of a bending displacement measuring device. For example, a plastic molded sample 2 to be measured is supported at both ends by the support mechanism 1 of the sample mounting table 10'.

In order to perform a deformation operation on the sample to be measured 2, for example, the robot mechanism section (A) 8 of the orthogonal robot device is used.
For example, a press rod 3 is attached to a six-axis force sensor 5 and a movable part of the force sensor 5 (a part that applies a load to the force sensor) via a connector to an arm (not shown) at the tip of the actuator part of a. ing.

On the other hand, in order to measure the displacement of the sample to be measured 2, for example, the robot mechanism part (
B) A displacement sensor 4, for example, a non-contact type triangular distance measuring displacement meter using a laser beam, is attached to an arm (not shown) at the tip of the actuator section 8b via a connector.

Now, when a pressing force command value of a certain level is given to the CPU 6, an operating current i of a certain level flows from the control device (A) 7a to drive a motor (not shown) of the robot mechanism part (A) 8a. Then, the pressing rod 3 connected to the force sensor 5 is moved to a predetermined position, and the sample to be measured 2 is pressed with the commanded pressing force. The movement position signal is sent to the control device (A) 7a and the CPU as an encoder output connected to the motor.
6 is fed back. Further, as the press rod 3 moves in the Z-axis direction, its tip contacts the sample to be measured 2 and presses and deforms it, the force is detected by the force sensor 5, and similarly a force signal is sent to the control device (A) 7a and the CPU 6. sent as.

Further, when the sample to be measured 2 is deformed, displacement data of the sample to be measured 2 is detected by the displacement sensor 4. Displacement at each position of the sample to be measured 2 can be measured while changing the position or angle of the displacement sensor 4 using the control device (B) 8b and robot mechanism section (B) 8b, and the position information and displacement data at each position can be measured by the CPU 6. being sent to.

The above force signal data and displacement data are sent to the CPU.
6, and the data is output and displayed on an X-Y plotter 9 in the form of, for example, bending displacement measurement data or strain-stress correlation data.

FIG. 5 is a diagram showing an example of a robot mechanism section, in which (a) is a top view and (b) is a side view. The robot mechanism units 8a and 8b are both mounted on a pedestal as shown in the figure, with the main body of the orthogonal robot mechanism unit having four degrees of freedom, for example, and the arm 8 at the tip of the actuator of each main body.
A force sensor 5 (pressing rod 3 at its tip) and a displacement sensor 4 are attached to 0a and 80b, respectively.

The sample 2 to be measured is supported at both ends by support mechanisms 1' of a sample mounting table 10', and the sample mounting table 10' is mounted on a sample mount separate from the mount of the main body. A connecting fitting with a flange (not shown) is connected to the force sensor 5, and the connecting fitting is connected to the arm 8 of one robot mechanism section 8a.
For example, it is connected to the tip of 0a by screwing. A pressing rod 3 is screwed to the force sensor movable portion on the opposite side. Further, the displacement sensor 4 is connected to the tip of the arm 80b of the other robot mechanism section 8b via a suitable connector, for example, by screwing.

FIG. 6 is a diagram showing an example of a conventional sample mounting table.
Figure (a) is a top view, and figure (b) is a side view. For example, the sample mounting table 10' has two pillars erected on the base, and the flat part at the upper end serves as the support mechanism 1', and both ends of the sample to be measured 2 are placed and supported in a well-balanced manner as shown in the figure. [See the broken lines in Figure (A) and Figure (B)].

Then, the center part of the sample to be measured 2 is deformed by vertically pressing it with, for example, a pressing rod 3 attached to a robot mechanism (not shown), and the displacement is measured by a displacement sensor (not shown). [Refer to the figure shown in the solid line in the same figure (b)].

[0015]

[Problems to be Solved by the Invention] The structure of the conventional supporting mechanism 1' for the sample to be measured 2 is simple because the sample to be measured 2 only needs to be placed thereon, and the operation is also extremely easy. It has its features.

However, the sample to be measured, such as a plastic molded product, is extremely easily deformed. For example, when a large deformation is applied as shown in FIG. will move.

For simplicity, it is assumed that the friction force acts in the horizontal direction on the support part, and if the friction force on the left support part is F1 and the friction force on the right support part is F2, then in general, F1
Since F2 and F2 are not equal, the sample to be measured 2
The appearance of the horizontal displacement will be different. For example, F
If 1<F2, the end of the sample to be measured 2 moves in the horizontal direction, that is, to the right, in the left support position as shown in FIG. 6(b). The value of frictional force is affected by the measurement conditions and the sample to be measured, and the sample to be measured moves to the right or left, resulting in inconsistent measurement conditions and poor measurement and calculation accuracy of bending deformation and strain-stress characteristics. There is a problem, and a solution is required.

[0018]

[Means for solving the problem] The above problem is solved by placing a sample 2 to be measured on a sample mounting table 10 equipped with a support mechanism 1 at both ends, and deforming the sample 2 by pressing it with a pressing rod 3. In the bending displacement measuring device that measures the amount of deformation using a displacement sensor 4, the support mechanism 1 of the sample mounting table 10 includes a mechanism that moves the support position of the sample to be measured 2 in a direction perpendicular to the pressing force. This problem can be solved by using a bending displacement measuring device. Specifically, the problem can be effectively solved if the moving mechanism of the support mechanism 1 is constituted by a rolling mechanism.

[0019]

[Operation] In the bending displacement measuring device of the present invention, the sample to be measured 2
The support mechanism 1 that supports both ends of the specimen 2 is configured by a mechanism that moves the support position of the sample 2 in a direction perpendicular to the pressing force, for example, a rolling mechanism using rolling bearings, so that the frictional force F1 at both left and right ends is reduced. = F2 ~ 0, horizontal movement is free at both ends regardless of the type of sample to be measured 2, and measurement conditions are always constant, improving measurement accuracy and calculation accuracy of bending deformation and strain-stress characteristics. That's what I do.

[0020]

[Embodiment] Figure 1 is a diagram showing an embodiment of the present invention.
A) is a top view, the same figure (b) is a sectional view along A-A' side, and the same figure (
c) is a structural diagram of the main parts.

In the figure, 10 is a sample mounting table of the present invention, 1 is a support mechanism thereof, 11 is a rotating shaft, and 12 is a rolling bearing. Note that the same reference numerals are given to the same parts as those explained in the above drawings, and the explanation of the same parts will be omitted.

[0022] The sample mounting table 10 includes, for example, an Al alloy base having a length of 450 mm, a width of 100 mm, and a thickness of 15 mm, with two Al alloy pillars erected at a predetermined distance, for example, 350 mm apart. A support mechanism 1 having a rolling mechanism with the same characteristics was provided at each upper end.

The support mechanism 1 of this embodiment is, for example, a round bar made of stainless steel with a diameter of 2 mm, and rolling bearings 12 are attached to both ends of the bar so that it can rotate with low frictional force.

The sample to be measured 2 has a length of 3, for example.
A plastic molded plate made of ABS resin having a size of 0.00 mm, a width of 30 mm, and a thickness of 3 mm was used, and both ends thereof were placed on the support mechanism 1, respectively.

The pressing rod 3 is made of stainless steel and has a diameter of 6 mmφ and a rounded tip of 3 mm SR. When the center part of the sample 2 to be measured placed on the sample mounting table 10 is pressed by the press rod 3 attached to the robot mechanism (not shown), the sample 2 to be measured is vertically moved as shown in the same figure (b). Although it moves horizontally at the same time as the displacement, the support mechanism 1
Since a rolling mechanism using rolling bearings is used, the frictional force at both the left and right ends is almost 0, and it can be seen that the horizontal movement of the sample to be measured 2 is free at both ends and moves the same distance. . As a result, the boundary conditions for measurement are always constant, greatly improving measurement accuracy.

FIG. 2 is a diagram showing an example of bending displacement measurement data, and FIG. This is an example of a graph displaying calculation data.

In the figure, (1) to (5) are the states in which the pressing force is gradually increased from 0, and in the figure (b), the vertical axis represents the strain, and the horizontal axis represents the position, that is, one end The distance from the surface of the sample to be measured 2 (the side being pressed) is shown.
The positive sign represents expansion strain, and the negative sign represents compressive strain. Note that the parameter is the magnitude of the pressing force.

The solid line represents the measurement results according to the above-mentioned embodiment of the present invention, and extremely stable data was obtained with high accuracy. On the other hand, when measuring using a sample mounting table with a conventional support mechanism, only compressive strain should normally occur due to imbalance in horizontal positional movement due to the difference in frictional force at both ends of the sample to be measured 2. , an abnormal measurement result occurs in which elongation strain occurs as shown by the broken line.

In other words, the measurement data of the conventional example does not represent the true characteristics of the sample to be measured 2, and is caused by the local force being unbalanced by the support mechanism. It can be seen that in the case of the invention example, the true characteristics of the sample 2 to be measured can be determined with high accuracy.

It goes without saying that the strain-stress characteristics of the sample to be measured 2 can be calculated from these data. FIG. 3 is a diagram showing another embodiment of the present invention, in which (A) is a top view and (B) is a side view.

In the figure, 13 is a slide bearing. In addition,
The same reference numerals are given to the same parts as those explained in the above drawings, and the explanation of the same parts will be omitted. The moving mechanism of the support mechanism 1 of this embodiment is constituted by a so-called well-known slide bearing 13.
A feature is that a plate made of, for example, an Al alloy is provided to bridge the slide bearing 13.

Therefore, the support mechanism 1 of this embodiment has the advantage that it can be applied to cases of special shapes such as the sample to be measured 2 having side ribs as shown in FIG.

[0033] The above embodiments are merely examples, and as long as the spirit of the present invention is met, preferred parts, configurations, dimensions, etc. may be used, or any combination thereof may be used. Needless to say.

[0034]

As explained above, according to the present invention, the support mechanism 1 that supports both ends of the sample to be measured 2 is a mechanism that moves the supporting position of the sample to be measured 2 in a direction perpendicular to the pressing force, for example, Since it is configured with a rolling mechanism using rolling bearings, the frictional force at both left and right ends F1 = F
2 to 0, the horizontal movement is free at both ends regardless of the type of sample to be measured 2, and the measurement conditions are always constant, improving the measurement accuracy and calculation accuracy of bending deformation and strain-stress characteristics. This greatly contributes to improving the performance of bending displacement measurement devices.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing an example of bending displacement measurement data.

FIG. 3 is a diagram showing another embodiment of the present invention.

FIG. 4 is a diagram showing a configuration example of a bending displacement measuring device.

FIG. 5 is a diagram showing an example of a robot mechanism section.

FIG. 6 is a diagram showing an example of a conventional sample mounting table.

[Explanation of symbols]

1 is a support mechanism; 2 is the sample to be measured, 3 is a pressing rod, 4 is a displacement sensor; 5 is a force sensor, 6 is the CPU, 7 (7a, 7b) is a control device; 8 (8a, 8b) is a robot mechanism section, 9 is an X-Y plotter, 11 is a rotation axis; 12 is a rolling bearing; 13 is a slide bearing;

Claims (2)

[Claims] [Claim 1] A sample to be measured (2) is placed on a sample mounting table (10) equipped with support mechanisms (1) at both ends, and the sample to be measured (2) is pressed by a pressing rod (3). In a bending displacement measuring device that deforms the sample and measures the amount of deformation using a displacement sensor (4), a support mechanism (1) of the sample mounting table (10) supports the sample to be measured (2) at right angles to the pressing force. A bending displacement measuring device characterized by having a mechanism for moving in a certain direction. 2. Claim 1, wherein the moving mechanism of the support mechanism (1) is constituted by a rolling mechanism.
The bending displacement measuring device described.