WO2017130448A1

WO2017130448A1 - Load detector

Info

Publication number: WO2017130448A1
Application number: PCT/JP2016/074116
Authority: WO
Inventors: 雅也瀬良; 治彦角谷; 大輔石本; 修一熊本; 健治武原
Original assignee: 三菱電機株式会社
Priority date: 2016-01-25
Filing date: 2016-08-18
Publication date: 2017-08-03
Also published as: CN108474701B; CN108474701A; TWI613139B; KR102008637B1; KR20180096713A; TW201726532A

Abstract

This load detector is provided with: a holding unit which comprises an inner ring part holding a shaft that supports a load, an outer ring part that is provided so as to surround the inner ring part and that is fastened to a mounting member by a fastening member through a plurality of mounting holes formed at intervals in a circumferential direction, and a spring part that is connected to the outer ring part at a spring part end radially extending from the inner ring; and a displacement detection unit which detects displacement of the inner ring part caused by a load. A mounting fixation portion which is a joint surface, of the fastening member, relative to the outer ring part is disposed at the circumferential edge of each of the mounting holes. In the outer ring part, a low-rigidity portion is formed between the mounting hole and the spring part end, and the low-rigidity portion has bending rigidity, in the circumferential direction, lower than that of other portions of the outer ring part.

Description

Load detector

The present invention relates to a load detector applied to a tension detector that detects the tension of a wire such as a web such as paper, cloth, film, or metal foil, or a cable.

It is necessary to control the tension acting on the web in order to prevent problems such as wrinkling, deflection, and printing misalignment in winding, printing, and processing of webs such as paper, cloth, film, and metal foil. The tension is controlled by detecting the tension acting on the web as a load acting on the roll around which the web is wound.
A load detector is used to detect the load acting on the roll. However, if the natural frequency of the load detector is low, there is a problem that the processing step cannot be speeded up due to vibration accompanying the web transfer. For this reason, a load detector with a high natural frequency is desired. For example, an elastic body to which a load is applied is a cantilever, and the neutral axis with respect to the bending moment of the cantilever is substantially matched with the center of the load. A load detector that increases the natural frequency of the detector is known (for example, see Patent Document 1).

Japanese Patent Laid-Open No. 3-246433 (FIG. 2)

In the load detector, the natural frequency of the load detector itself can be increased, but the influence of installation of the load detector on the installation member on the detection performance is not taken into consideration.
Examples of detection performance that is greatly affected by installation include an increase in hysteresis of the detection performance and a decrease in natural frequency accompanying an increase in hysteresis.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a load detector having a high natural frequency, easy installation on an installation member, and low hysteresis.

A load detector according to the present invention is fastened to a mounting member by a fastening member through an inner ring portion that holds a shaft that supports a load, and a plurality of mounting holes that are provided around the inner ring portion and spaced apart in the circumferential direction. A holding unit composed of an outer ring part and a spring part connected to the outer ring part at a spring part end extending in a radially outward direction from the inner ring part;
A displacement detector for detecting the displacement of the inner ring caused by the load,
A load detector having an installation fixing part which is a joint surface of the fastening member to the outer ring part at a peripheral part of the installation hole,
The outer ring portion is formed with a low rigidity portion between the mounting hole and the end of the spring portion, and the bending rigidity in the circumferential direction of the low rigidity portion is the bending rigidity of other portions of the outer ring portion. Low compared to

According to the load detector of the present invention, the low rigidity portion is formed between the mounting hole of the outer ring portion and the end of the spring portion, and the bending rigidity in the circumferential direction of the low rigidity portion is different from that of the outer ring portion. Since it is lower than the bending rigidity of the part, it can provide a load detector structure that has high natural frequency, easy installation, and low detection performance hysteresis, thus further improving the detection accuracy of the load detector It has a remarkable effect on the expansion of the application range of the detector.

It is a figure which shows the installation structure of the load detector which concerns on Embodiment 1 of this invention. FIG. 2 is a cross-sectional view taken along line II-II in FIG. It is a front view which shows the load detector of FIG. It is a perspective view which shows the holding | maintenance unit of FIG. It is an enlarged front view which shows the modification of the low-rigidity part of FIG. It is an enlarged front view which shows the modification of the low-rigidity part of FIG. It is an enlarged front view which shows the modification of the low-rigidity part of FIG. It is an enlarged front view which shows the modification of the low-rigidity part of FIG. It is an enlarged front view which shows the modification of the low-rigidity part of FIG. It is an enlarged front view which shows the modification of the low-rigidity part of FIG. It is a modification of the load detector of FIG. 1, Comprising: It is a front view which shows the load detector provided with the mechanism which prevents the damage of a spring part. It is an enlarged view which shows the mechanism which prevents the damage of the spring part of FIG. It is a modification of the load detector of FIG. 1, Comprising: It is a front view which shows the load detector from which the structure of a spring part differs. It is a modification of the load detector of FIG. 1, Comprising: It is a front view which shows the load detector from which the structure of a spring part differs. It is a modification of the load detector of FIG. 1, Comprising: It is a front view which shows the load detector from which a detection structure differs. It is a front view which shows the spacer used for installation of the load detector of FIG. It is a side view which shows the installation structure of the load detector using the spacer of FIG. It is a front view which shows the load detector of FIG. 1 comprised with several components. It is a disassembled front view of the load detector of FIG. It is a front view which shows the load detector which concerns on Embodiment 2 of this invention. It is an enlarged view which shows the spring part of FIG. It is a front view which shows the load detector which concerns on Embodiment 3 of this invention. It is explanatory drawing explaining the bending moment which acts on the load detector of FIG. It is explanatory drawing explaining the bending moment which acts on the load detector of FIG. It is a front view which shows the load detector which concerns on Embodiment 4 of this invention. It is a front view which shows the load detector which concerns on Embodiment 5 of this invention.

Hereinafter, the load detector according to each embodiment of the present invention will be described with reference to the drawings. In the drawings, the same or equivalent members and parts will be described with the same reference numerals.

Embodiment 1 FIG.
1 is a diagram showing an installation configuration of a load detector 5 according to Embodiment 1 of the present invention, FIG. 2 is a cross-sectional view taken along the line II-II in FIG. 1, and FIG. FIG. 4 is a front view showing the load detector 5, and FIG. 4 is a perspective view showing the holding unit 8 of FIG.
In FIG. 1, the X-axis direction is the width direction of the load detector 5, the Y-axis direction is the height direction of the load detector 5, and the Z-axis direction is the depth direction of the load detector 5. A sign is used. The load detected by the load detector 5 acts in the −Y direction.

The load detector 5 of this embodiment is fixed to the installation member 7 and detects a load F in the Y-axis direction that acts on the load detector 5 via the roll axis 3.
As shown in FIG. 2, the load F acting on the load detector 5 is a resultant force of the tension T of the web 1, and the tension T is expressed by the following equation.
T = (F−W) / 2 cos θ (1)
Here, θ is the holding angle shown in FIG. 2, W is the weight of the roll 2a, and by measuring the load F, the tension T can be obtained from the equation (1).
Since a proportional relationship is established between the load F and the displacement, and between the load F and the strain, the load F can be detected by measuring the displacement or strain generated in the constituent members of the load detector 5. .

The web 1 to be detected such as paper, cloth, film, metal foil or the like is wound around the first roll 2a, the second roll 2b, and the third roll 2c and transferred. Bearings 4 are fitted into both ends of the roll axis 3 that is the shaft of the first roll 2a. A load detector 5 installed on the installation member 7 is attached to each bearing 4.

The load detector 5 includes a holding unit 8 that receives a load F in the Y-axis direction from the roll shaft center 3, and a differential transformer 9 that is a displacement detection unit that measures displacement generated in the constituent members of the holding unit 8 due to the load F. It is equipped with.
The holding unit 8 includes an inner ring portion 10 into which the bearing 4 is fitted and receives a load from the roll shaft center 3, and an annular outer ring portion 11 that is formed outside the inner ring portion 10 and is fixed to the installation member 7. And two spring portions 12 extending in the radial direction connecting the inner ring portion 10 and the outer ring portion 11.
The inner ring portion 10 includes an annular load support portion 10a and a core fixing portion 10b extending from the load support portion 10a in the X-axis direction.
The outer ring portion 11 is formed at three equal intervals, and is installed with a mounting hole 11a to which a bolt or the like is attached to be fixed to the installation member 7, and an installation fixing portion located in a range of 1 mm to 10 mm around the installation hole 11a 11b, a low-rigidity portion 11c formed between a spring portion end 12a that is a connection portion between the outer ring portion 11 and the spring portion 12, and a planar measuring instrument fixing portion 11d on which the differential transformer 9 is installed. Have. The low-rigidity portion 11c has a reduced radial thickness of the outer ring portion 11 due to the notch. That is, the radial thickness of the low-rigidity portion 11 c is smaller than the radial thickness of other portions of the outer ring portion 11. Thereby, the low-rigidity part 11c has the bending rigidity of the circumferential direction low compared with the other site | part of the outer ring | wheel part 11. FIG.
Here, the bending rigidity means a value obtained by multiplying the Young's modulus E of the material of the outer ring portion 11 and the cross-sectional secondary moment I in the circumferential direction.

In the holding unit 8, the inner ring portion 10 and the outer ring portion 11 are connected by a spring portion 12 extending in the radial direction from the load support portion 10a, and the first roll 2a, the second roll 2b, and the third roll 2c are connected to each other. Depending on the attachment method to the web 1, the load is received in both the + Y direction and the −Y direction. The center of the inner ring hole 10c of the inner ring portion 10 to which the bearing 4 is attached coincides with the load center A.

The differential transformer 9 has a differential transformer core 9b fixed to the core fixing part 10b of the inner ring part 10, and a differential transformer coil 9a fixed to the measuring instrument fixing part 11d of the outer ring part 11. The relative displacement in the Y-axis direction between the differential transformer coil 9a and the differential transformer core 9b is measured.
The load detector 5 receives a load F in the Y-axis direction acting from the roll axis 3 at the load support portion 10a via the bearing 4, and measures the displacement generated in the core fixing portion 10b as the spring portion 12 is bent. Measurement is performed with the differential transformer 9 installed in the fixed portion 11d.
In this load detector 5, the displacement of the measuring instrument fixing portion 11d to which the differential transformer coil 9a is fixed is smaller than the displacement of the core fixing portion 10b. It can be regarded as a displacement in the Y-axis direction of 10b.

Next, hysteresis that greatly affects the detection performance of the load detector 5 will be described.
Hysteresis is a phenomenon in which the detection output of the load F is different before and after the load F is applied, and the slight displacement of the joint surface caused when the load F is applied cannot be completely restored even after the load F is removed. Is the main cause.
As described above, the load detector 5 is often installed using bolts. However, if a slight deviation occurs in the joint surface of the installation / fixing portion 11b when a load is applied, the frictional force acting on the joint surface of the installation / fixation portion 11b is applied. Even after the load is removed due to the effect of, the deviation remains and hysteresis occurs.
The minute shift that occurs in the installation / fixing portion 11b is caused by a bending moment acting on the installation / fixation portion 11b due to the load F in the Y-axis direction. Therefore, in order to reduce the hysteresis, it is important to reduce the bending moment acting on the installation / fixing portion 11b.
In the load detector 5 according to the first embodiment, a bending moment is generated from the load support portion 10a through the spring portion end 12a and the low rigidity portion 11c to the installation fixing portion 11b due to the load F in the Y-axis direction. Since the bending rigidity of the portion 11c is smaller than other portions of the outer ring portion 11, the low rigidity portion 11c is preferentially deformed, and the bending moment acting on the installation fixing portion 11b can be reduced.
Therefore, the shift | offset | difference which arises in the joint surface of the installation fixing | fixed part 11b can be reduced, and a hysteresis can be made small.
In addition, since the displacement of the joint surface such as bolt fastening can be reduced, the load detector 5 having a high natural frequency can be manufactured.

In the load detector 5 shown in FIG. 3, the installation holes 11 a are three and are arranged uniformly in the circumferential direction of the outer ring portion 11. However, if the load detector 5 can be fixed to the installation member 7, the installation holes 11 a are arranged. There are no particular restrictions on the number and position of the.

For example, the low-rigidity portion 11c is not limited to the shape shown in FIG. 5, but may have the shapes shown in FIGS. FIG. 5 shows that the outer ring part 11 is provided with a rectangular notch from the inner ring side or the outer ring side of the outer ring part 11 to reduce the outer ring width, and the bending rigidity is higher than other parts of the outer ring part. It is small. FIG. 6 is a low-rigidity portion in which a part of the notch in FIG. 5 is formed in an arc shape, and FIG. 7 is a low-rigidity portion formed by providing a round hole at the tip of the slit. Is relaxed with a round hole. FIG. 8 shows a low-rigidity portion formed by providing a round hole in the outer ring portion 11 and only the hole processing, so that the processing cost can be reduced. FIG. 9 is a low-rigidity part formed by notching the outer ring part 11 from the inner and outer peripheral sides of the outer ring part 11, and FIG. 10 is a low-rigidity part formed by providing a plurality of slits. It is.
Further, the low-rigidity part 11c may make the outer ring part 11 thinner in the Z-axis direction.
The number and shape of the low-rigidity portion 11c are not particularly limited as long as the bending rigidity in the circumferential direction of the low-rigidity portion 11c is smaller than other portions of the outer ring portion 11.
In production, the bending rigidity can be effectively reduced by reducing the width of the outer periphery of the outer ring portion 11 corresponding to the low-rigidity portion as shown in FIG.
In addition, the inventor of the present application has applied the load detector 5 when the bending rigidity in the circumferential direction of the outer ring portion 11 of the low rigidity portion 11c is 1/8 or less of the bending rigidity of other portions of the outer ring portion 11. It has been experimentally obtained that the hysteresis is remarkably improved. For example, when the bending rigidity in the circumferential direction of the low-rigidity portion 11c is set to one-eighth of the bending rigidity of other portions of the outer ring portion 11, the hysteresis is about half that when the low-rigidity portion is not provided in the outer ring portion 11. It became.

11 is a modification of the load detector 5 of FIG. 1, and is a front view showing the load detector 5 provided with a stopper 13a that is a mechanism for preventing damage to the spring portion 12, and FIG. 12 is a stopper of FIG. It is an enlarged view which shows 13a.
The stopper 13 a is fixed at the base end portion to the outer ring portion 11. The tip of the stopper 13 a is directed to the load center A and faces the outer peripheral surface of the inner ring portion 10, and a gap is formed between the inner ring portion 10 and the stopper 13 a.
Other configurations are the same as those of the load detector 5 shown in FIG.

In this load detector 5, the load support portion 10a does not contact the stopper 13a at a load less than the allowable load of the load detector 5, but when a load exceeding the allowable load is applied, the outer periphery of the load support portion 10a Is in contact with the stopper 13a and the deformation of the spring portion 12 is suppressed, so that the spring portion 12 is prevented from being damaged.
The material and shape of the stopper 13a are not specified as long as it has a function of preventing the spring portion 12 from being damaged. For example, if a bolt such as a set screw is used as the stopper 13a, the tip of the stopper 13a and the load support portion 10a The outer peripheral gap can be easily adjusted.

FIG.13 and FIG.14 is a front view which is a modification of the load detector 5 of FIG. 3, and shows the load detector 5 from which the structure of the spring part 12 differs.
In the spring portion 12 of the first embodiment, a displacement necessary for detection is generated in the core fixing portion 10b of the inner ring portion 10 due to bending of the spring portion 12 due to a bending moment generated by the load F in the Y-axis direction, and the spring portion 12 is broken. As long as the structure does not, the shape, number, and symmetry are not particularly limited.
The example of FIG. 13 has two parallel spring portions 12 that connect the outer ring portion 11 and the inner ring portion 10, and the displacement behavior of the core fixing portion 10b is close to parallel to the load direction due to the truss structure. The linearity of the detected load can be improved.
The example of FIG. 14 has one spring portion 12 that connects the outer ring portion 11 and the inner ring portion 10, and the spring portion 12 is easily bent by a bending moment that acts on the spring portion 12 due to the load F in the Y-axis direction. In short, the displacement of the core fixing portion 10b can be increased.
Therefore, the detection output increases, and the load detector 5 that is resistant to disturbance can be realized.
If the spring portion 12 has a line-symmetric structure with respect to a straight line in the X-axis direction passing through the load center A, the core fixing portion 10b takes the same displacement behavior before and after reversal even if the direction of the load F is reversed. Therefore, the load detector 5 with good load detection symmetry can be realized.
Further, since the bending moment generated at the spring end 12a by the load F is proportional to the distance in the X-axis direction from the load center A, if the spring portion 12 is at a position where the distance from the load center A in the X-axis direction becomes large. The deflection of the spring portion 12 is increased, and the displacement of the core fixing portion 10b can be increased.
Therefore, the detection output increases, and the load detector 5 that is resistant to disturbance can be realized.

The position and shape of the core fixing portion 10b, which is a displacement measurement location, are not particularly limited. However, since the displacement generated in the core fixing portion 10b due to the bending of the spring portion 12 can be increased, the position is separated from the spring portion end 12a in the X axis direction. It is desirable to provide the core fixing part 10b and the differential transformer core 9b.

FIG. 15 is a front view showing another detection structure of the load detector 5 according to the first embodiment.
In the load detector 5 shown in FIG. 3, the load F is detected by measuring the displacement generated in the core fixing portion 10 b using the differential transformer 9. In this modification, the spring portion is used instead of the differential transformer 9. 12 is affixed with a strain gauge 14. The strain gauge 14 is a deformation detection unit that detects the deformation amount of the spring portion 12 that is deformed by the load F, that is, the strain amount of the spring portion 12. The load F is detected based on the deformation amount measured by the strain gauge 13.
Other configurations are the same as those of the load detector 5 shown in FIG.

In this modification, the load F can be detected even if the displacement generated in the inner ring portion 10 is reduced by using the strain gauge 14 having high detection sensitivity to the deformation of the spring portion 12. That is, since the bending rigidity of the spring portion 12 can be increased, the load detector 5 that can support the inner ring portion 10 firmly and stably and has a high natural frequency can be realized.
Further, the differential transformer 9 is eliminated, and the processing of the core fixing part 10b of the inner ring part 10 and the measuring instrument fixing part 11d of the outer ring part 11 is not required, and the structure is compared with the load detector 5 shown in FIG. It can be simplified.

16 is a front view showing a spacer 6 used for installing the load detector 5 of FIG. 1, and FIG. 17 is a side view showing an installation configuration of the load detector 5 using the spacer 6 of FIG.
In this example, the front surface and the back surface of the load detector 5 are sandwiched between the spacers 6 shown in FIG. 16, and the load detector 5 is fixed to the installation member 7 via the case 15. Thereby, both end surfaces in the axial direction of the holding unit 8 are covered with the case 15. Moreover, the case 15 is arrange | positioned through each of the inner ring | wheel part 10 and the spring part 12, and a clearance gap.
The spacer 6 plays a role in which the inner ring portion 10 and the spring portion 12 do not come into contact with other members such as the installation member 7 in the installed state, and when the load F acts, the deformation of the inner ring portion 10 and the spring portion 12 is another member. To prevent it from being disturbed by friction.
The structure of the spacer 6 is not specified unless the inner ring portion 10 and the spring portion 12 are in contact with other members in the installed state.
Further, a case 15 covering the entire surface stretched between the X axis and the Y axis of the holding unit 8 except for the portion through which the roll axis 3 passes is attached to the outer side of each spacer 6 as shown in FIG. The load detector 5 is protected from external dust and contact.
If the case 15 has a structure that contacts only the outer ring portion 11 and does not contact the inner ring portion 10 and the spring portion 12, the spacer 6 is not necessary, so that the workability can be improved by reducing the number of parts. it can.
Further, the thickness of the inner ring portion 10 and the spring portion 12 in the Z-axis direction may be made smaller than that of the outer ring portion 11 to prevent contact, thereby making the spacer 6 unnecessary.

18 is a front view showing the load detector 5 of FIG. 1 constituted by a plurality of parts, and FIG. 19 is an exploded front view of the load detector 5 of FIG.
The holding unit 8 shown in FIG. 3 is composed of a single part, but in this example, it is composed of a plurality of parts.
In the load detector 5, the outer ring portion 11 is a separate component from the inner ring portion 10 and the spring portion 12. As shown in FIG. 19, the outer ring portion 11 and the spring portion 12 are combined with a flat portion 12 b of the spring portion end 12 a and a flat portion 11 f of the outer ring concave portion 11 e and fixed with bolts or the like.
If the outer ring part 11 and the spring part 12 can be fixed, the fixing method is not particularly limited.
By providing a fitting between the side surface 12c of the spring portion end 12a and the side surface 11g of the outer ring recess 11e, the spring portion 12 can be aligned, and the fixing position of the spring portion 12 can be easily determined.
Even if a single part has a complicated structure, the structure per part can be simplified by dividing it into a plurality of parts, and extrusion and pressing can be performed, thereby reducing manufacturing costs.
In addition, a structure in which the thickness of the inner ring portion 10 and the spring portion 12 in the Z-axis direction is smaller than that of the outer ring portion 11 can be easily manufactured by extrusion molding or the like. Thereby, since the spacer 6 used at the time of installation becomes unnecessary, the number of parts is reduced and workability is improved. Further, by providing a large width of the outer ring recess 11e to which the spring portion end 12a is fixed, not only the spring end 12a is fixed, but also a structure having a low rigidity portion 11c can be provided.
Examples of the material of the holding unit 8 include, for example, iron-based materials such as carbon steel, high-tensile steel, rolled steel, stainless steel, and structural alloy steel, and plated steel based on them, or aluminum, magnesium, titanium, You may use materials, such as brass and copper, and alloy materials.
Since the holding unit 8 shown in FIG. 18 has a simple shape extruded in the Z-axis direction, it can be extruded. In particular, the use of an aluminum alloy increases the production efficiency and reduces the weight of the load detector 5. Can be achieved.

Embodiment 2. FIG.
20 is a front view showing the load detector 5 according to Embodiment 2 of the present invention, and FIG. 21 is an enlarged view showing the spring portion 12 of FIG.
As shown in FIG. 20, the load detector 5 according to the second embodiment includes two L-shaped spring portions 12 that are symmetrical with respect to a straight line passing through the load center A in the X-axis direction. The spring portion 12 extends radially outward from the outer peripheral portion of the load support portion 10 a, bends at a point B that is a bending point of the spring portion 12, forms an L shape, and is connected to the outer ring portion 11. . A gap is formed in the radial direction of the outer ring portion 11 between the spring portion 12 and the outer ring inner peripheral surface 13b. Thereby, between the outer ring | wheel part 11 and the spring part 12, the area | region where the space | interval of the outer ring | wheel inner peripheral surface 13b of the outer ring | wheel part 11 and the surface of the spring part 12 facing this outer ring | wheel inner peripheral surface 13b becomes constant. Existing.
Other configurations are the same as those of the load detector 5 shown in FIG.

According to the load detector 5 of this embodiment, since the bending moment generated in the spring portion 12 by the load F in the Y-axis direction is proportional to the distance in the X-axis direction from the load center A, if the distance is large, A large bending moment acts on the bending point B of the spring portion 12, and the spring portion 12 is deformed.
By increasing the distance a in the X-axis direction between the load center A and the point B, which is the bending point of the spring portion 12, the displacement generated in the core fixing portion 10b increases, and the differential transformer 9 attached to the core fixing portion 10b increases. The detection output increases, and the load detector 5 that is strong against disturbance can be obtained.
In addition, by adjusting the size of the gap between the spring portion 12 and the outer ring inner peripheral surface 13b, the spring portion 12 does not come into contact with the outer ring inner peripheral surface 13b when the load is less than the allowable load of the load detector 5, but the allowable load is reduced. When a load exceeding the load is applied, the spring portion 12 comes into contact with the inner peripheral surface 13b of the outer ring, and deformation of the spring portion 12 when a load exceeding the allowable load is applied is suppressed. Damage can be prevented.
Accordingly, it is not necessary to separately provide a stopper 13a for preventing damage to the spring portion 12 shown in FIG. 12, and therefore, the number of parts of the load detector 5 can be reduced and the assembly workability is improved.
Further, as shown in FIG. 20, there is a region where the distance is constant between the outer ring inner peripheral surface 13b of the outer ring portion 11 and the surface of the spring portion 12 facing the outer ring inner peripheral surface 13b.
Therefore, when a load exceeding the allowable load is applied to the load detector 5, the contact is made in a region where the interval is constant, so that the contact area is larger than that of the irregularly shaped contact. Therefore, the contact stress is reduced, and damage to the contact portion can be suppressed.

Embodiment 3 FIG.
FIG. 22 is a front view showing a load detector 5 according to Embodiment 3 of the present invention.
In the load detector 5 according to the third embodiment, the outer ring portion 11 is a separate component from the inner ring portion 10 and the spring portion 12, and has two L-shaped spring portions 12.
The spring portion 12 extends in the radial direction from the outer peripheral portion of the load support portion 10 a, is bent at a point B that is a bending point of the spring portion 12, has an L shape, and is connected to the outer ring portion 11.
The spring part end 12a is provided at a position where the distance b in the X-axis direction between the flat part 12b of the spring part 12 and the load center A becomes small. The spring part end 12a is fitted into the outer ring recess 11e and fixed with a bolt or the like. Thus, the holding unit 8 is configured.
The fixing method is not particularly limited as long as the outer ring portion 11 and the spring portion 12 can be fixed. Further, the position of the spring portion end 12a is such that the smaller the distance b in the X-axis direction between the flat portion 12b of the spring portion end 12a and the load center A, the bending acting on the spring portion end 12a due to the load F in the Y-axis direction. This is preferable because the moment is reduced.
In addition, in the load detector 5 shown in FIG. 22, by providing a large outer ring recess 11e to which the spring portion end 12a is fixed, not only the spring end 12a is fixed, but also the outer ring recess 11e includes a low rigidity portion 11c. Yes.
In the state where the outer ring portion 11 and the spring portion 12 are fixed, a gap is generated in the radial direction of the outer ring portion 11 between the outer ring inner peripheral surface 13b and the spring portion 12. The gap has a function of preventing damage to the spring part by suppressing the deformation of the spring part 12 when the spring part 12 comes into contact with the inner peripheral surface 13b of the outer ring when a load exceeding the allowable load is applied. The center of the inner ring hole 10c of the inner ring portion 10 to which the bearing 4 is attached coincides with the load center A.

According to the load detector 5 in FIG. 22, the bending moment acting on the point B of the spring portion 12 can be increased by the load F in the Y-axis direction, while the flat portion 12b of the spring portion end 12a and the load center A By reducing the distance b in the X-axis direction, the bending moment acting on the spring portion end 12a can be reduced.
That is, by increasing the deflection of the spring portion 12, the displacement generated in the core fixing portion 10b can be increased, and the displacement of the joint surface between the spring portion end 12a and the outer ring recess 11e can be reduced, and the spring portion 12 and the outer ring portion 11 can be reduced. It is possible to reduce the hysteresis that occurs between the mounting and fixing portion 11b. In particular, when the distance b is zero, the bending moment acting on the spring portion end 12a is minimized, and the hysteresis is most reduced. Further, the displacement of the joint surface can be reduced, and the natural frequency of the load detector 5 can be increased.

Next, the bending moment that acts on the spring portion end 12a will be described with reference to FIGS. 23 and 24. By reducing the distance b, the bending moment of the outer ring recess 11e can be reduced.
FIG. 23 shows a beam along the X-axis direction and the Y-axis direction. A load W is applied to the point P in the −Y direction, and the beam is completely fixed at the point S.
FIG. 24 is a beam obtained by rotating the beam of FIG. 23 counterclockwise by θ, and similarly to FIG. 23, a load W is applied to the point P in the −Y direction and is completely fixed at the point S.
The point P, point Q, point R, and point S in FIGS. 23 and 24 correspond to the point D, point C, point B, and spring portion end 12a in FIG. 22, respectively.
Note that point C is a joint between the load support portion 10a and the spring portion 12, and point D is an intersection of a straight line in the Y-axis direction passing through the load center A and the load support portion 10a. The bending moment M due to the load F at the point S in FIGS. 23 and 24 is expressed by the following equation.
M = F (L1-L2) (2)
Therefore, the bending moment acting on the point S corresponding to the spring portion end 12a is proportional to the distance (L1-L2) from the point P to the point S in the direction perpendicular to the load direction, regardless of the beam angle, and the bending moment. Is minimum when the distance (L1-L2) is zero.
Further, the holding unit 8 of the load detector 5 of the second embodiment shown in FIG. 20 has a long and narrow gap between the outer ring inner peripheral surface 13b and the spring portion 12, but has a complicated structure. In the load detector 5 of this embodiment shown in FIG. 4, the outer ring portion 11, the inner ring portion 10 and the spring portion 12 which are individual parts constituting the holding unit 8 have a simple structure, and therefore, extrusion molding, press working, etc. Thus, the manufacturing cost can be suppressed.
Further, if the thickness of the inner ring portion 10 and the spring portion 12 in the Z-axis direction is smaller than that of the outer ring portion 11, the inner ring portion 10 and the spring portion 12 do not come into contact with other members such as the installation member 7 in the installed state. The deformation of the inner ring portion 10 and the spring portion 12 is not hindered by friction with other members, and the spacer 6 becomes unnecessary.
Further, the two spring parts 12 have a line-symmetric structure with respect to a straight line in the X-axis direction passing through the load center A as shown in FIG. 22, and even if the direction of the load F is reversed in the positive and negative directions, the core fixing part 10b takes the same displacement behavior as before reversal, and the load detector 5 with good load detection symmetry can be realized.

Embodiment 4 FIG.
FIG. 25 is a front view showing a load detector 5 according to Embodiment 4 of the present invention.
In the load detector 5 according to the fourth embodiment, the two spring portions 12 connect the inner ring portion 10 and the outer ring portion 11 and are arranged symmetrically with respect to a straight line in the Y-axis direction passing through the load center A. Yes.
The pair of spring portions 12 are bent by the bending moment due to the load F in the Y-axis direction, and the displacement generated in the core fixing portion 10b is measured by the differential transformer 9 installed in the measuring device fixing portion 11d.
The core fixing portion 10b and the differential transformer 9 are installed on a straight line in the Y-axis direction that passes through the load center A, which is a symmetric line of the spring portion 12. As long as the spring part 12 is line symmetrical with respect to the straight line in the Y-axis direction passing through the load center A, the structure and the number are not particularly limited.

In the load detector 5 shown in the first to third embodiments, when the spring portion 12 is deformed by the bending moment due to the load F in the Y-axis direction, the core fixing portion 10b, which is a displacement measurement point, takes a circular arc behavior. Compared with the case of the linear behavior, the linearity of the measured displacement with respect to the load is reduced.
On the other hand, in the load detector 5 shown in FIG. 25, the spring portion 12 has a line-symmetric structure with respect to a straight line in the Y-axis direction passing through the load center A, and the core fixing portion when the load F acts. Since 10b takes a linear behavior, the linearity of the measured displacement is improved, and the load detection accuracy can be improved.
In addition, the holding unit 8 of Embodiment 4 may be comprised from several components instead of a single component structure.

Embodiment 5 FIG.
FIG. 26 is a front view showing a load detector 5 according to Embodiment 5 of the present invention.
In the load detector 5 of the fifth embodiment, as shown in FIG. 26, the outer ring portion 11 is a separate component from the inner ring portion 10 and the spring portion 12, and two L symmetrical with respect to the load center A. This is a structure provided with a letter-shaped spring portion 12.
The spring portion 12 of the fifth embodiment has the same mechanism as the spring portion 12 of the third embodiment shown in FIG. 22 except that it is point-symmetric with respect to the load center A.

According to the load detector 5 of the fifth embodiment, as with the load detector 5 of the fourth embodiment, when the load F in the Y-axis direction acts on the load support portion 10a, the core fixing portion 10b moves linearly. Therefore, the linearity of the measured displacement is better than the circular arc behavior, and the load detection accuracy can be improved.
Further, the spring portion 12 increases the distance a in the X-axis direction between the load center A and the point B of the spring portion 12 and increases the bending moment acting on the point B of the spring portion 12, while the spring portion 12 The distance b in the X-axis direction between the flat portion 12b and the load center A is reduced to reduce the bending moment acting on the spring portion end 12a.
Therefore, after increasing the displacement generated in the core fixing portion 10b, it is possible to reduce the hysteresis caused by the displacement of the joint surface between the spring portion end 12a and the outer ring recess 11e.
Moreover, since the shift | offset | difference of the joint surface between the spring part end 12a and the outer ring | wheel recessed part 11e can be reduced, the natural frequency of the load detector 5 can be made high.
In addition, since the pair of spring portions 12 of the fifth embodiment has a point-symmetric structure with respect to the load center A, even if the direction of the load F is reversed, the core fixing portion 10b is A load detector having the same displacement behavior as that before the reversal and having good load detection symmetry can be realized.
The holding unit 8 of the fifth embodiment may have a single component structure.

In the load detector 5 of each of the above embodiments, the web 1 has been described as an object to be applied to the rolls 2a to 2c, but a wire such as a cable may be used.
Further, the configuration of the web 1 and the rolls 2a to 2c is not specified. For example, the web 1 may be attached to the rolls 2a to 2c in the opposite direction.
If the roll 2a can be supported, the load detector 5 may support only one end, not the both ends of the roll axis 3, and the other end may not be supported but may be a free end.
Moreover, although the bolt which is a fastening member was used for fixation with respect to the installation member 7 of the load detector 5, this is an example and fastening members, such as a screw, may be sufficient. In this case, the installation fixing part 11b is a part to which a force for fixing the load detector 5 to the installation member 7 acts. Furthermore, the strain gauge 14 may be applied not only to the first embodiment but also to the spring portion 12 of the second to fifth embodiments.

1 Web (detection target), 2a, 2b, 2c roll, 3 roll shaft center, 4 bearing, 5 load detector, 6 spacer, 7 installation member, 8 holding unit, 9 differential transformer (displacement detection unit), 9a difference Dynamic transformer coil, 9b differential transformer core, 10 inner ring part, 10a load support part, 10b core fixing part, 10c inner ring hole, 11 outer ring part, 11a installation hole, 11b installation fixing part, 11c low rigidity part, 11d measuring instrument fixing Part, 11e outer ring recess, 11f flat part, 11g side face, 12 spring part, 12a spring part end, 12b flat part, 12c side face, 13a stopper, 13b outer ring inner peripheral face, 14 strain gauge (deformation detection part), 15 case.

Claims

From the inner ring portion that holds the shaft that supports the load, the outer ring portion that surrounds the inner ring portion and is fastened to the installation member by the fastening member through the plurality of installation holes that are formed at intervals in the circumferential direction, and the inner ring portion A holding unit composed of a spring part connected to the outer ring part at a spring part end extending in a radially outward direction;
A displacement detector for detecting the displacement of the inner ring caused by the load,
A load detector having an installation fixing part which is a joint surface of the fastening member to the outer ring part at a peripheral part of the installation hole,
The outer ring portion is formed with a low rigidity portion between the mounting hole and the end of the spring portion, and the bending rigidity in the circumferential direction of the low rigidity portion is the bending rigidity of other portions of the outer ring portion. Low load detector compared to.
From the inner ring portion that holds the shaft that supports the load, the outer ring portion that surrounds the inner ring portion and is fastened to the installation member by the fastening member through the plurality of installation holes that are formed at intervals in the circumferential direction, and the inner ring portion A holding unit composed of a spring part connected to the outer ring part at a spring part end extending in a radially outward direction;
A deformation detection unit that detects a deformation amount of the spring portion that is deformed by the load,
A load detector having an installation fixing part which is a joint surface of the fastening member to the outer ring part at a peripheral part of the installation hole,
The outer ring portion is formed with a low rigidity portion between the mounting hole and the end of the spring portion, and the bending rigidity in the circumferential direction of the low rigidity portion is the bending rigidity of other portions of the outer ring portion. Low load detector compared to.
The load detector according to claim 1 or 2, wherein the outer ring part is a separate part from the spring part and the inner ring part.
The spring portion is provided in two or more, and each of the spring portions is arranged symmetrically with respect to a straight line that passes through the center of the inner ring portion and is perpendicular to the load direction. The load detector according to claim 1.
The spring part is provided in two or more, and each of the spring parts is arranged in line symmetry with respect to a straight line that passes through the center of the inner ring part and extends in the direction of the load. The load detector according to item 1.
4. The spring part according to claim 1, wherein two or more spring parts are provided, and each of the spring parts is arranged point-symmetrically with respect to the center of the inner ring part. Load detector.
The spring part is connected to the outer ring part through the bending point from the inner ring part, and at a distance in a direction perpendicular to the straight line of the load passing through the center of the inner ring part, the spring part is separated from the straight line. The load detector according to any one of claims 1 to 6, wherein the distance to the bending point is larger than the distance from the straight line to the end of the spring portion.
The load detector according to claim 7, wherein there is a region in which a distance between an outer ring inner peripheral surface of the outer ring portion and a surface of the spring portion facing the outer ring inner peripheral surface is constant.
The load detector according to any one of claims 1 to 6, further comprising a stopper having a proximal end portion fixed to the outer ring portion and a distal end portion facing the outer peripheral surface of the inner ring portion via a gap. .
The displacement detector includes a differential transformer coil fixed to the outer ring portion and a differential transformer core fixed to the inner ring portion and relatively displaced with respect to the differential transformer coil. The load detector according to any one of claims 1 and 3 to 9.
The load detector according to any one of claims 1 to 10, wherein a thickness of the low-rigidity portion in a radial direction is smaller than a radial thickness of other portions of the outer ring portion.
Both end surfaces in the axial direction of the holding unit are covered with a case,
The load detector according to any one of claims 1 to 11, wherein the case is disposed with a gap between each of the inner ring portion and the spring portion.