JP2730596B2 - Structural deformation detector - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structural deformation detector for detecting deformation occurring in structures constituting various machines and mechanisms.

[Related Art] For various machines, the magnitude of a force generated when the machine is used is detected, and the machine is controlled based on the detected value, or various analyzes are performed on the machine. A means of doing so is employed. Hereinafter, a press machine employing such means will be described as an example.

FIG. 10 is a side view of the press machine. In the drawing, 1 is a frame having a box shape as a whole, 2 is a hydraulic cylinder fixed to the bottom of the frame 1, 3 is a piston of the hydraulic cylinder 2, 4 is hydraulic oil of the hydraulic cylinder 2, and 5 is a hydraulic oil of the piston 3. The lower plank 6 connected to the end is an upper plank connected to the upper part of the frame 1 and facing the lower plank 6. Reference numeral 7 denotes a work placed between the lower thick plate 5 and the upper thick plate 6. Hydraulic cylinder 2
When the pressurized oil is supplied, the piston 3 extends upward, whereby the work 7 is pressed.

When the work 7 is pressed, an upward force is generated on the lower thick plate 5 and a downward reaction force is generated on the upper thick plate 6, and these forces are transmitted through the frame 1. A part of the transmission path is indicated by a chain line 8. This force is not equal on the left and right sides of the figure, and the magnitude differs depending on each path. In particular, depending on the shape of the work and the position where the work is placed, the load is unloaded, and accordingly, the frame is deformed unequally in the right and left directions. When the above-mentioned force is generated by press working,
The above-described deformation occurs in the frame 1, and this deformation causes a small error in the processing dimension of the work 7, thereby lowering the processing accuracy. Therefore, if the correction is performed based on the deformation of the frame 1, the processing is thereby performed. It is possible to prevent a decrease in accuracy.

Knowing the magnitude of such a force is necessary not only for drive control of the hydraulic cylinder 2 for performing appropriate pressing, but also for processing the work 7 with high accuracy.

Conventionally, the above-mentioned force has been detected by measuring the hydraulic pressure of the hydraulic cylinder 2. However, since this is an indirect means, the magnitude of the force cannot be accurately known. It is impossible to know. Therefore, means for directly detecting force by attaching a strain gauge to the force transmission path 8 of the frame 1 is employed. These strain gauges is shown at S ₁ to S ₄ in FIG. 10. By using this way a strain gauge S ₁ to S _4, it is possible to detect a force directly, and can know the deformation of the frame 1. The strain gauges S ₁ and S ₂ are frame 1
And the strain gauges S ₃ and S ₄ detect the shear deformation of the frame 1.

The means for detecting such a force is applied not only to a machine but also to a structure. An application example is shown in FIG. FIG. 11 is a side view of the hopper. 9 is a hopper, 10 is a supporting column of the hopper 9, and 11 is a table. A strain gauge S is attached to an appropriate position of each support column 10. With these strain gauges S, the deformation of each support column 10 due to the weight of the hopper and the stored item is detected, and the weight of the stored item can be known based on the detected value.

[Problems to be Solved by the Invention] By the way, in the above-mentioned conventional force detecting means, since means for directly attaching a strain gauge to a structure causing deformation is adopted, it is necessary to appropriately attach a strain gauge. Not only requires much labor and time, but also there is a possibility that the part or the entire surface may be peeled off after sticking, resulting in a problem of lack of stability and reliability.

Furthermore, the deformation that occurs in the structure is extremely small, and therefore, the amount of strain in the strain gauge is also small, and it has not been possible to obtain a detection value with satisfactory accuracy.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems in the prior art, and to provide a deformation detector for a structure that can perform high-precision detection with high reliability and that can be easily mounted. .

Means for Solving the Problems To achieve the above object, the present invention provides a first block comprising a fixed portion attached to a surface of a structure to which a force is transmitted and an extension extending from the fixed portion. A second block consisting of a fixed portion attached to the same surface as the surface of the structure and an extension extending from the fixed portion and facing the extension of the first block; the first block and the second block. A structural deformation detector is constituted by a connecting member for elastically connecting between the extension blocks of the second block and a displacement detecting means provided between the respective extension portions and detecting a displacement between the respective extension portions. It is characterized by the following.

Furthermore, the present invention is characterized in that, in addition to the above-described configuration, at least one of the extension portions is provided with a temperature detecting means near the displacement detecting means.

[Operation] When a force acts on the structure to cause expansion and contraction or shear deformation, a displacement corresponding to the deformation is generated between the fixed portions of the first block and the second block. This displacement appears between an extension of the first block and an extension of the second block located opposite each other. This displacement is detected by the displacement detecting means. In each extension that is not fixed to the surface of the structure to form a free end, the movement in the vertical direction with respect to the surface of the structure is restricted by the coupling member. Due to this action of the coupling member, the two extension portions are displaced and deformed only in the direction to be detected, and only the required deformation is given to the displacement detecting means, and the deformation in the other direction is not given. Is detected.

In another aspect of the present invention, a temperature detecting means is provided near one of the displacement detecting portions in one or both of the extended portions to detect the temperature of the structure, and correct a deformation error caused by the temperature.

[Example] Hereinafter, the present invention will be described based on an illustrated example.

1 (a) and 1 (b) are plan views of a deformation detector according to an embodiment of the present invention. In the figure, 1 is the frame shown in FIG. Reference numeral 10 denotes a deformation detector of the present embodiment. Reference numeral 11 denotes a first block body, which is fixed to the frame 1 and has fixed portions 11a,
Bolts 11b ₁ , 11b _{2 for} fixing fixing part 11a and fixing part 11a
And an extension 11c extending from the frame 1 in the direction of expansion and contraction of the frame 1. Also, 12 is the second block member provided to face the first block body 11, the fixing portion 12a fixed to the frame 1, the bolts 12b _1, 12 for fixing the fixing portion 12a
b ₂ and an extended portion 12 c extending from the fixed portion 12 a in the direction of expansion and contraction of the frame 1. The extension portions 11c and 12c extend in parallel to each other and are free ends with respect to the frame 1.

Reference numerals 13a and 13b denote thin plate-shaped flat plates that connect the extension portions 11c and 12c vertically, and are in parallel with each other. Flat plates 13a, 13b
Is easily elastically deformed in the direction of expansion and contraction of the frame 1, but exhibits high rigidity against forces in other directions. 14 is the extension
It is a shear plate connected between 11c and 12c, and its thickness is much smaller than the thickness of the extension portions 11c and 12c. 1
Reference numerals 5a and 15b denote strain gauges adhered to the front and back surfaces of the shear plate 14, and the resistance value changes due to expansion and contraction. The four front and back strain gauges are configured in a bridge circuit (not shown).

In such a structure, when a force as indicated by an arrow in FIG. 1 (b) is transmitted to the frame 1, the frame 1 expands and contracts, and the relative displacement between the extension portions 11c and 12c is changed. As a result, the flat plates 13a and 13b and the shear plate 14 are deformed as shown. It should be noted that the size of each deformation is illustrated in a greatly exaggerated manner in the figure. Due to the deformation of the shear plate 14 as shown in the drawing, the strain gauge 15a is elongated, and the strain gauge 15b is contracted (similar expansion and contraction is also caused in each of the strain gauges attached to the back surface). The bridge circuit outputs a signal proportional to the deformation, and thus a signal proportional to the force applied to the frame 1 and the expansion and contraction deformation.

In the deformation detector 10, the expansion and contraction deformation generated in the frame 1 appears as an expanded strain on the shear plate between the extension portions 11c and 12c. The strain expansion rate is determined by the fixed parts 11a, 12
The distance between the fixed points of a is h, and the distance between each extension 11c and 12c is l
Then, it becomes h / l.

As described above, in the present embodiment, two blocks are fixed to the frame, the extension portions which are free ends of the blocks are opposed to each other, a shear plate is provided between the extension portions, and a strain gauge is attached to the shear plate. Since it is designed to detect deformation, it is not necessary to attach a strain gauge directly to the frame, just attach the deformation detector to the frame,
As compared with the case where the strain gauge is directly attached to the frame, the possibility of contact with another object is reduced, and the reliability and stability can be increased. In addition, since the deformation can be expanded to the shear plate as strain, more accurate detection is possible. Furthermore, since the flat plate is provided between the two extension portions, the movement of the extension portions in the direction perpendicular to the frame can be restricted, and the detection accuracy can be further improved.

2 (a) is a plan view of a specific example of the deformation detector shown in FIG. 1 (a), and FIG. 2 (b) is a line II shown in FIG. 2 (a).
It is sectional drawing in alignment with b-IIb. In each figure, the same or equivalent parts as those shown in FIG. In this example, the first block 11 and the second block 11
Block 12 and flat plates 13a and 13b are formed by end milling one rectangular block. That is,
A hole from the right side near one end of the square block with an end mill
By forming 16a, the fixing portion 1 of the first block 11 is formed.
1a and an extension 11c are formed. Similarly, a hole 16b is formed from the left side near the other end of the square block by an end mill, thereby forming a fixed portion 12a and an extension 12c of the second block 12. Further, between the two extension portions 11c and 12c, and the hole 16
The flat plates 13a and 13b are formed by drilling holes 17a and 17b at locations close to a and 16b with an end mill. Finally, hole 17
The shear plate 14 is formed by cutting the block between a and 17b from the front and back to a predetermined thickness. Reference numeral 19 denotes a silicon rubber plate laid between the frame 1 and the deformation detector. The gap between each of the holes 16a, 16b, 17a, 17b and the extension portions 11c, 12c and the silicone rubber plate 19 is filled with a heat conductive silicone rubber. 18a and 18b are extensions 11c and 12c near the shear plate 14.
Is a temperature gauge adhered to the wall surface of FIG.

With this configuration, the processing becomes extremely easy, and a good thermal equilibrium can be obtained between the deformation detector and the frame by laying the silicon rubber plate and filling with the heat conductive silicon rubber. Accuracy can be increased. Further, by providing the temperature gauge, the temperature generated in the frame can be detected, and the deformation due to the temperature can be corrected based on the detected temperature.

3 and 4 are views showing displacement detecting means other than the displacement detecting means constituted by the shear plate and the strain gauge shown in FIG. 1 (a). The same reference numerals are given to the same or equivalent parts as those shown, and the description is omitted.

FIG. 3 is a plan view of a deformation detector using displacement detecting means including a flexure and a strain gauge. In the figure, reference numeral 21 denotes a plate-shaped flexure portion connected between the extension portions 11c and 12c, and reference numeral 22 denotes a flexure portion 21 attached to a strain gauge. Due to the expansion and contraction deformation of the frame 1, the same deformation as the deformation of the flat plates 13a and 13b shown in FIG. 1 (b) occurs in the bending portion 21, and the resistance value of the strain gauge 22 changes according to the deformation. Thereby, the expansion and contraction deformation of the frame 1 is detected.

FIG. 4 is a plan view of a deformation detector using a differential transformer as displacement detecting means. In the figure, reference numeral 11d denotes a protrusion protruding from the extension 11c toward the extension 12c, and 12d denotes a protrusion protruding from the extension 12c toward the extension 11c. Reference numeral 24 denotes an iron core fixed to the protrusion 11d, and reference numeral 25 denotes a winding provided on the protrusion 12d. Due to the expansion and contraction deformation of the frame 1, the protrusion 11
An enlarged displacement occurs between d and 12d, and the amount inserted into the winding 25 of the iron core 24 is determined according to the displacement, whereby the output of the winding 25 changes and the expansion and contraction deformation of the frame 1 is detected. can do.

FIG. 5 is a plan view of a deformation detector using a displacement detecting means composed of a piezoelectric element. In the figure, 11d and 12d are the same protrusions as those shown in FIG. Reference numeral 27 denotes a piezoelectric element provided between each of the protrusions 11d and 12d. A displacement occurs between the protruding portions 11d and 12d due to the expansion and contraction of the frame 1, and the piezoelectric element 27 is pressurized according to the displacement, and an electric signal corresponding to the displacement is output. Thereby, the expansion and contraction deformation of the frame 1 can be detected.

FIG. 6 is a plan view of a deformation detector having displacement detecting means using capacitance. In the figure, 11d and 12d are the same protrusions as shown in FIGS. 4 and 5, 29a and 29b are the protrusions 1 respectively.
These electrodes are provided on 1d and 12d and face each other. Displacement occurs between the protruding portions 11d and 12d due to expansion and contraction of the frame 1,
The distance between the electrodes 29a and 29b changes according to the displacement, and this change is captured as a change in the capacitance between the two electrodes. Thereby, the expansion and contraction deformation of the frame 1 can be detected.

FIG. 7 is a plan view of a deformation detector having displacement detecting means using light. In the figure, 11d and 12d are the same protrusions as those shown in FIG. 31a, 31b is a light guide made of glass fiber or the like provided at a predetermined interval on the protrusion 11d,
32 is a reflection surface provided on the protruding portion 12d. The light guide 31b guides light from a light source (not shown) and emits the light to the reflection surface 32. The light guide 31a receives the reflected light from the reflection surface 32 and introduces the incident light to a light amount detector (not shown). Now, when the frame 1 undergoes expansion and contraction, displacement occurs between the protrusions 11d and 12d. Due to this displacement, the light guides 31a, 31b and the reflecting surface 32
Is changed, and the light guide 31a is changed in accordance with the change amount.
Also changes the amount of incident light. Therefore, the expansion and contraction deformation of the frame 1 can be detected by detecting the amount of incident light.

The deformation detector using these displacement detecting means has the same effect as the deformation detector shown in FIG.

In the above description, expansion and contraction deformation is exemplified as the deformation of the structure. However, it is apparent that shear deformation can be detected by changing the installation direction of the deformation detector. That is, FIG. 8 (a) is a plan view of a deformation detector for shear deformation, and FIG. 8 (b) is FIG. 8 (a).
9 (a) is a plan view of another deformation detector for shear deformation, and FIG. 9 (b) is a cross-section along line IXb-IXb of FIG. 9 (a). FIG. In each figure, the same or equivalent parts as those shown in FIG. The functions and effects of these deformation detectors are the same as those of the deformation detector shown in FIG.

Note that the structure is not limited to the frame of the press machine. Further, the number of flat plates may be one, or three or more.

[Effects of the Invention] As described above, in the present invention, the deformation of the structure is concentrated on the displacement detecting means between the extensions of the blocks, so that the deformation of the structure is detected with high accuracy. can do. In addition, since the deformation in the direction other than the direction to be detected is limited by the coupling member, only the required deformation is given to the displacement detecting means, thereby ensuring highly accurate detection. In addition, more stable and reliable detection can be performed as compared with a means of directly attaching a strain gauge to a structure. Further, in the case where a temperature gauge is provided, deformation due to temperature can be corrected based on the temperature detected by the temperature gauge, so that better and more accurate detection can be performed.

[Brief description of the drawings]

1 (a) and 1 (b) are plan views of a deformation detector according to an embodiment of the present invention, and FIGS. 2 (a) and 2 (b) show the structure of the deformation detector shown in FIG. 1 (a). FIGS. 3, 4, 5, 6, and 7 are a plan view and a side sectional view showing one specific example, FIGS. 3, 4, 5, 6, and 7 are plan views of a deformation detector using different displacement detecting means, and FIGS. 9 (a) and 9 (b) are plan and side sectional views of another deformation detector for detecting shear deformation, and FIGS. 10 and 10. FIG. 11 is a side view of the press machine and the hopper. 1 ... frame, 10 ... displacement detector, 11 ... first block, 11a, 12a ... fixed part, 11c, 12c ... extended part, 12 ...
2nd block, 13a, 13b ... flat plate, 14 ... shear plate, 1
5a, 15b, 22 …… Strain gauge, 18a, 18b …… Temperature gauge,
21 ... flexure part, 24 ... iron core, 25 ... winding, 27 ... piezoelectric element, 29a, 29b ... electrode, 31a, 31b ... light guide, 32 ... reflection surface.

Claims (4)

(57) [Claims] 1. A first block comprising a fixed portion attached to a surface of a structure to which a force is transmitted and an extension extending from the fixed portion, a fixed portion attached to the same surface as the surface of the structure, and a first block. A second block extending from the fixed portion and extending from the first block and facing the extension of the first block; and a coupling member for elastically coupling between the first block and the second block. And a displacement detection means provided between the extension portions and detecting displacement between the extension portions. 2. The method according to claim 1, wherein the connecting member comprises:
A structural deformation detector, wherein two displacement detectors are provided at intervals, and the displacement detecting means is disposed between the intervals. (3) In claim (1) or (2),
A structural deformation detector, wherein the coupling member is a flat elastic member that can be deformed only in a displacement direction. 4. A first block comprising a fixed portion attached to a surface of a structure to which a force is transmitted and an extension extending from the fixed portion, a fixed portion attached to the same surface as the surface of the structure, and a first block. A second block extending from the fixed portion and extending from the first block and facing the extension of the first block; and a coupling member for elastically coupling between the first block and the second block. A displacement detection means provided between the extension parts to detect a displacement between the extension parts, and a temperature detection means provided in the vicinity of the displacement detection means in at least one of the extension parts. A structural deformation detector.