JP5655727B2 - Load measuring device - Google Patents

Description

  The present invention relates to a load measuring device, and in particular, a load measuring device suitable for measuring a tensile load or a compressive load in a wide range of deformation speeds including high-speed deformation essential for characteristic evaluation of an impact absorbing member typified by an automobile structure. About.

In the automotive industry, the development of a vehicle body structure that can reduce injury to passengers during a collision is an urgent issue, and in order to optimize the collision deformation behavior of the vehicle body, individual members and their combined structures It is extremely important to understand the deformation characteristics.
Therefore, conventionally, characteristic evaluation of the member has been performed by a quasi-static method in which the member is deformed at a low speed using a large compression tester or the like.

However, actual collision deformation occurs at high speed, which is different from behavior under quasi-static load. In particular, it is known that buckling, which is important in a thin plate structure often used in automobiles, behaves differently depending on whether the load is dynamic or quasi-static.
For this reason, in order to grasp the dynamic deformation characteristics, a drop weight test, that is, a test that causes a drop weight to collide with a fixed member from the top to cause a dynamic deformation is performed. It was trying to be close to the deformation.

However, since it is necessary to evaluate the absorbed energy at the time of impact deformation of the member for characteristic evaluation, the evaluation of the absorbed energy requires measurement of the crush distance of the member and the crushing load at that time. In a typical test, it was actually difficult to measure the crush load.
That is, when a dynamic load is measured with a load cell used in a normal quasi-static test, the impact elastic wave reflects and propagates through the load cell during measurement, and the load due to the propagation of the impact elastic wave is reduced. Since vibration is generated and superimposed, there is a problem that the impact elastic wave affects the measurement of the measurement load, thereby preventing a true load measurement.

  Regarding the dynamic load measuring method as described above, in order to measure the stress-strain relationship of the material, for example, in Patent Document 1, when the dynamic deformation characteristics of the test specimen are measured, the action starting point of the dynamic load is measured. In the apparatus in which the support structure is linearly arranged, the action starting point, the test body, the load detection unit, the load detection unit support structure are arranged in this order, and the load detection unit is cylindrical. Yes, the ratio of the diameter D (mm) to the length L (mm) satisfies 0.3 ≦ L / D ≦ 3, and (the cross-sectional area of the load detection unit) <(the support structure of the load detection unit) A cross-sectional area) is shown. In addition, when it is necessary to support the test body, the action starting point, the test body, the support section of the test body, the load detection section, and the support structure are arranged in this order, and (cross-sectional area of the load detection section) <( A load measuring device that satisfies the condition of the cross-sectional area of the support portion of the test body is described.

  The load measuring device described in Patent Document 1 can perform a relatively accurate load detection even when a dynamic load is detected, but an eccentric load acts on a load detection unit that detects a load. In this case, a complicated bending moment is generated in the load detection unit. In particular, in the case of a test on a complex structure that has been increasing in recent years, it is often impossible to specify at which position the tensile load or the compressive load acts, and therefore there is a high possibility that an eccentric load acts on the load detection unit.

  At this time, even in the load measuring device described in Patent Document 1, it is possible to measure the load acting in the axial direction of the load detection unit, but when an eccentric load is applied, as described above. Since a complicated bending moment is generated in the load detector, it is considered that accurate load measurement cannot be performed due to the influence of the bending moment. There is also a problem that the measurement accuracy is likely to change depending on the position of the strain gauge attached to the load detection unit. Furthermore, since stress concentrates on a part of the load detection unit due to the eccentric load, and part of the load detection unit may be intensively deformed, the load detection unit that is originally supposed to be elastically deformed is used. There is a possibility that plastic deformation may occur, and it is considered that accurate load measurement cannot be performed.

JP 2006-284514 A

  The technical problem of the present invention is to provide a load measuring device capable of accurately measuring a load even when an eccentric load is applied when measuring a high-precision tensile load or compressive load in a wide range of deformation speeds including high-speed deformation. It is to provide.

In order to solve the above problems, a load measuring device according to the present invention is provided with a columnar load detection unit for measuring a tensile load or a compressive load, and one end side in the axial direction of the load detection unit. A load measuring member having a contact portion to be actuated and a support portion provided on the other end side, a cylinder portion covering the load measuring member around the axis of the load detecting portion in a non-contact manner with the load measuring member, and A spherical shape that holds the contact part and the support part in the cylinder part interposed between the inner peripheral surface of the cylinder part and the contact part and the support part of the load measuring member facing the inner peripheral surface of the cylinder part. A plurality of cylindrical rolling elements,
The above-mentioned rolling element is in point contact with each outer peripheral surface of the contact portion and the support portion, and the contact portion and the support portion displaced by the tensile load or the compressive load are arranged along the inner peripheral surface of the cylindrical portion. The load measuring member is arranged so that the load detecting member is formed in a cylindrical shape, and is orthogonal to the axis of the load detecting portion in the contact portion and the support portion. The cross-sectional area of the cross section is larger than the cross-sectional area of the cross section orthogonal to the axis in the load detection unit .

In the present invention, as described above, the load measuring member has the load detecting portion formed in a columnar shape, and the cross-sectional area of the cross section orthogonal to the axis of the load detecting portion in the contact portion and the support portion. is formed larger than the cross-sectional area of a cross section orthogonal to the axial line of the load detecting unit, yet the rolling elements, it is assumed that contact each outer peripheral surface and the point of the contact portion and the support portion.
Therefore, since reflection / interference of stress waves in the load detection unit of each load measurement member can be promoted, early saturation of the stress wave in the load detection unit related to the load to be measured is achieved, and the load detection unit It becomes possible to eliminate the influence of the disturbance of the propagation of the stress wave in the. Therefore, it is possible to measure the tensile load or the compressive load in a wide range of deformation speeds including high-speed deformation essential for the characteristic evaluation of the shock absorbing member represented by the automobile structure with higher accuracy.

In the present invention, the load measuring member may be formed integrally with the load detection unit and at least one of the contact unit and the support unit.
Furthermore, in the present invention, the rolling element can be formed using a material having a density different from that of the material of the contact part and the support part .
In addition, the load measuring device of the present invention can be a load measuring device for measuring impact loads.

According to the present invention, the load measuring member is covered around the axis of the load detecting unit in a non-contact manner with the load measuring member at the cylindrical portion, and a plurality of load measuring members are provided between the cylindrical portion and the contact portion and the support portion of the load measuring member. The contact portion / support portion displaced by a tensile load or a compressive load is guided along the inner peripheral surface of the cylindrical portion in the axial direction of the load detecting portion. Even if an eccentric load is applied to the contact portion or the support portion, the entire contact portion or the entire support portion can be displaced in the axial direction of the load detection portion while maintaining these postures.
Thereby, since it is suppressed that a complicated bending moment generate | occur | produces in a load detection part, a tensile load or a compressive load can be measured with high precision.
Furthermore, since the direction in which the contact portion and the support portion are displaced is limited to the axial direction of the load detection portion, the concentration of deformation due to the eccentric load of the load detection portion is suppressed, so that the plastic deformation of the load detection portion is prevented. Is prevented.

It is a top view which shows typically the load measuring device which concerns on this invention. FIG. It is explanatory drawing explaining the raise process of the load of a load detection part. It is sectional drawing which shows typically a motion of the load measuring device when a load acts on a contact part. It is a figure explaining reflection of the stress wave by a rolling element. It is the graph which compared the measurement result about the load measuring device which concerns on this invention, and the conventional load measuring device.

  1 and 2 show an embodiment of a load measuring device according to the present invention. The load measuring device of this embodiment is a load provided with a columnar load detector 2 for measuring a tensile load or a compressive load. The measuring member 1, the cylinder part 3 which covers this load measurement member 1 around the axis line of the load detection part 2, and the some rolling element 4 interposed between this cylinder part, a contact part, and a support part are provided. ing.

The load measuring member 1 has a contact having a load surface 2a formed in a columnar shape and a contact surface 5a provided on one end side in the axial direction of the load detector 2 for applying a tensile load or a compressive load. It has the part 5 and the support part 6 provided in the other end side of the load detection part.
In this embodiment, the load detection unit 2 is configured such that its axis extends in the vertical direction, and the contact surface 5a is configured with the upper end side of the load detection unit 2 as the contact portion 5 and the lower end side as the support portion 6. Is provided upward on the upper surface side of the contact portion 5. Therefore, the load measuring member 1 has a mode in which the load detection unit 2 is sandwiched between the lower surface side of the contact unit 5 and the upper surface side of the support unit 6 as a whole.

A strain gauge (not shown) is affixed to the outer peripheral surface of the load detector 2, and the load can be calculated from the surface strain measured by the strain gauge. The reason why the load detection unit 2 is a solid cylinder is to make the load distribution in the cross section uniform, thereby improving the accuracy of load measurement using a strain gauge.
This point will be described in detail. When an eccentric load is applied to the load detection unit, if stress is concentrated on a part of the load detection unit, local deformation is likely to occur in the part, and The deformation is a complex deformation in which compression deformation and shear deformation are mixed. Since stress waves, which will be described in detail later, change in speed due to deformation of a propagating object, when such a complicated deformation occurs in the load detection unit, the load detection unit is subjected to stress waves having different propagation speeds. Will pass with a time difference. Such a time difference between stress waves appears as noise at the time of load detection, and as a result, highly accurate load measurement may be hindered.
For this reason, in this embodiment, the load detector is a solid cylindrical shape, and the load distribution in the cross section is made uniform to prevent local deformation concentration, thereby causing simple deformation as much as possible. The change of the speed of the stress wave in the load detection unit is prevented, the stress wave is prevented from passing with a time difference, and noise at the time of load detection is eliminated.
The length in the axial direction of the load detector 2 is preferably as short as possible within the range where the strain gauge can be attached. This allows time for the stress wave to propagate throughout the load detector 2 during load measurement. Since it can reduce, the early saturation in the load detection part 2 of the stress wave mentioned later can be promoted further.

In the load measuring member 1, the load detection unit 2, the contact unit 5, and the support unit 6 are integrally formed with each other by appropriate means such as shaving.
The load detection unit 2, the contact unit 5, and the support unit 6 are integrally formed in the load measuring member 1, that is, at the joint between the load detection unit 2, the contact unit 5, and the support unit 6. This prevents the occurrence of noise due to the vibration during load measurement, thereby improving the accuracy of load measurement.
Furthermore, the load detection unit 2, the contact unit 5, and the support unit 6 are made of a metal material having a high Young's modulus, such as iron, as a whole, and the stress wave propagation speed described later in the load measuring member 1 is made as much as possible. To be able to speed up.

By the way, in this load measuring member 1, the said contact part 5 and the support part 6 are each formed in the column shape of the same shape and the same size as shown in FIG.1 and FIG.2, and both are load detection parts. The cross-sectional areas At and As of the cross section orthogonal to the axis 2 (in this case, the horizontal cross section) are set to be larger than the cross-sectional area Ak of the cross section orthogonal to the axis of the load detector 2. Therefore, the relationship among the sizes of the cross-sectional areas Ak, At, As of the horizontal cross sections of the load detection part, the contact part, and the support part in the load measuring member 1 is At = As> Ak.
Here, the cross-sectional areas At and As of the cross section orthogonal to the axis of the load detection unit 2 in the contact part 5 and the support part 6 are formed larger than the cross-sectional area Ak of the cross section orthogonal to the axis of the load detection unit 2. This is because the saturation of the stress wave in the load detection unit 2 is completed earlier.
Hereinafter, this point will be specifically described.

When an impact load is applied to the test body, high-speed deformation occurs in the test body. At this time, the tensile load or compression load f applied to the test body, that is, the load generated in the load measuring member 1 is as shown in FIG. It is measured so as to rise stepwise and reach a load F of 100% after lapse of Δt time. This is because when the stress wave is transmitted through the load detection unit 2, reflection on the end face of the load detection unit 2, interference of stress waves in the load detection unit 2, and the like are repeated, and the stress wave is gradually saturated.
When a dynamic test is performed, the stress wave is first reflected and interfered inside the load detection unit 2 to make the internal deformation uniform. At that time, in order to perform high-speed and high-accuracy load measurement, it is necessary to quickly saturate reflection / interference in the load detector 2 that causes stress wave noise.

Therefore, in order to accurately measure the load at the time of high-speed deformation of the test body, the time Δt at which the load becomes unstable is obtained by saturating the reflection / interference of the stress wave in the load detector 2 at an early stage. It is important to shorten it.
In view of this point, the inventors pay attention to a plurality of step portions of the load to be measured, and increase the load corresponding to these step portions relative to the load F to be measured, thereby increasing the load. It was found that the load transmitted to the detector 2 can reach the load F at an early stage and the time Δt can be shortened.

In order to increase the load corresponding to the step relative to the load F, it is effective to increase the reflectance of the stress wave in the load detection unit 2 and saturate the stress wave early. The inventors have found that there is.
Also, when the stress wave travels from a small area to a large area, the reflectivity increases and the reflection increases, and when the stress wave travels from a large area to a small area However, in the area of the large cross-sectional area, the influence of the disturbance of stress wave propagation is very large, but when the process proceeds from the small area to the large area, the influence of the disturbance of stress wave propagation is hardly affected in the small area. I knew I would n’t. Furthermore, it has been found that the greater the difference in cross-sectional area, the greater the stress wave reflectance.

Therefore, in this embodiment, the cross-sectional area of the horizontal cross section of the load detection unit 2 is made smaller than the cross-sectional areas of the horizontal cross sections of the contact unit 5 and the support unit 6.
As a result, it is possible to increase / promote reflection of stress waves in the load detection unit 2 and to promote interference, to saturate the stress waves early, and to influence the disturbance of propagation of stress waves in the load detection unit 2 As a result, the time Δt is shortened, and the load detection unit 2 can perform load measurement with higher accuracy.

On the other hand, the cylindrical portion 3 has a substantially circular inner peripheral surface in plan view having a larger diameter than the contact portion 5 and the support portion 6 of the load measuring member 1, and the height of the entire load measuring member 1, that is, A cylindrical member that has a height substantially the same as the axial length of the load detector in the load measuring member 1 and that extends linearly in the axial direction of the load detector (in the vertical direction in this embodiment), It is made of metal such as iron with excellent rigidity.
The cylindrical portion 3 is formed such that a plan view shape on the inner peripheral surface side is concentric with a circle which is a plan view shape of the contact portion 5 and the support portion 6, and the load measuring member 1 is connected to the load measuring member 1. 1 is accommodated in the hollow in a non-contact state. Therefore, the cylindrical portion 3 has the outer periphery of the contact portion 5 and the support portion 6 through a space that is not in contact with each other between the inner peripheral surface of the cylindrical portion 3 and the outer peripheral surface of the contact portion 5 and the support portion 6. The outer peripheral surface of the load measuring member 1 is covered along the surface.

Further, the rolling element 4 has an opposing surface (that is, the contact portion 5 and the contact portion 5 of the cylindrical portion 3 and the inner peripheral surface of the cylindrical portion 3 in the support portion 6 of the load measuring member 1). Between the contact portion 5 and the support portion 6 and the inner peripheral surface of the cylindrical portion 3, respectively, and the load measuring member 1 as a whole. Is held in the cylindrical portion 3.
And this rolling element 4 can roll in the axial direction of the load detection part 2 in the specific position in the cylinder part 3, Thereby, when a tensile load or a compressive load acts, the load The contact portion 5 and the support portion 6 displaced by the above are guided in the axial direction of the load detecting portion 2 along the inner peripheral surface of the cylindrical portion 3.

  In this embodiment, as shown in FIG. 1 and FIG. 2, spherical elements formed of metal are adopted as the rolling elements 4, and each rolling element 4 is connected to each outer periphery of the contact portion 5 and the support portion 6. In addition to making point contact with the surface, it is configured to be able to roll in the direction in which the contact portion 5 and the support portion 6 are guided in the vertical direction on the inner peripheral surface of the cylindrical portion 3, and as a result, as shown in FIG. 4. In addition, when a load is applied, the entire contact portion 5 or the entire support portion 6 can be guided in the vertical direction while maintaining the initial posture. In addition, the white arrow in FIG. 4 shows a load.

Here, the spherical element is adopted as the rolling element 4, as shown in FIG. 5, by reducing the contact range between the rolling element 4 and the contact part 5 / support part 6 as much as possible. This is to increase the reflectance of the stress wave from the support part 6 and reflect the load acting on the contact part 5 and the support part 6 as much as possible without escaping to the outside (the arrow in FIG. 5 indicates the direction of the stress wave). .) Thereby, it is possible to suppress the attenuation of the stress wave due to the load acting on the contact portion 5 and the support portion 6 as much as possible, and to achieve early detection of the stress wave and high accuracy detection of the true load in the load detection unit 2. I can do it.
In addition, it is preferable to use a material having a density different from the material of the contact portion / support portion from the relationship of the stress wave reflectivity as the metal material forming the rotator. In this case, a material such as aluminum can be used as the rotator. However, it is not always necessary to use a material having a density different from that of the contact portion / support portion, and the rolling element can be selected as appropriate.

In this embodiment, as shown in FIG. 1, the rolling element 4 is provided between the cylindrical portion 3 and the contact portion 5 and between the cylindrical portion 3 and the support portion 6. Each of the rolling elements 4 is disposed at equal intervals on the opposite sides of the load measuring member 1 so that the entire contact portion 5 or the entire support portion 6 is connected to the axis of the load detection portion 2. It can be stably displaced in the direction.
Further, as shown in FIG. 2, each rolling element 4 is disposed at a height that makes contact with each middle stage of the contact portion / support portion when no load is applied to the contact portion / support portion. .

Meanwhile, a groove 7 that holds each of the rolling elements 4 between the cylindrical portion 3 and the contact portion 5 and the support portion 6 is formed around the axial direction of the load detecting portion 2 on the inner peripheral surface of the cylindrical portion 3. That is, each of the rolling elements 4 is formed in the circumferential direction of the cylindrical portion 3 so that it does not move in the axial direction of the load detecting portion 2 on the inner peripheral surface of the cylindrical portion 3.
As a result, even when the contact portion 5 or the support portion 6 is displaced in the axial direction of the load detection portion 2 due to the load, each of the rolling elements 4 rolls on the spot without moving following the displacement. The contact part 5 and the support part 6 can be stably guided along the inner peripheral surface of the cylinder part 3 in the axial direction of the load detection part 2.

  In the load measuring device having the above-described configuration, the support portion 6 is fixed to a rigid body, and the test body is made to collide with the contact surface 5a of the contact portion 5 or the test body is placed on the contact surface 5a. A compressive load or a tensile load is applied to the contact portion 5 by applying an impact to the test body with a falling weight or the like, and the load is measured by the load detection portion 2.

At this time, the load measuring member 1 is covered in a non-contact state around the axis of the load detecting unit 2 by the cylindrical portion 3, and the cylindrical portion 3, the contact portion 5 and the support portion 6 of the load measuring member 1, and the like. A plurality of rolling elements 4 are interposed between the contact parts 5 and the support parts 6 displaced by the tensile load or the compressive load by the rolling elements 4 along the inner peripheral surface of the cylindrical part 3. 2, even if an eccentric load is applied to the contact portion 5 or the support portion 6 to be displaced, the cylindrical portion 3 and the rolling element 4 are in the axial direction of the load detection portion. Correct in this case (vertical direction).
As a result, the entire contact portion 5 or the entire support portion 6 can be displaced in the axial direction of the load detection portion 2 while maintaining the initial posture, and therefore a complicated bending moment may be generated in the load detection portion 2. Thus, the load detecting unit 2 can measure the tensile load or the compressive load in the axial direction of the load detecting unit 2 with high accuracy.
Furthermore, since the direction in which the contact portion 5 and the support portion 6 are displaced is limited to the axial direction of the load detection portion 2, the concentration of deformation due to the eccentric load of the load detection portion 2 can be suppressed. 2 plastic deformation is also prevented.

In addition, the load detection unit 2, the contact unit 5, and the support unit 6 of each load measuring member 1 are integrally formed, and the contact unit 5 and the support unit 6 are larger than the cross-sectional area of the cross section perpendicular to the axis of the load detection unit 2. Since the cross-sectional area of the cross section orthogonal to the axis of the load detection unit 2 is formed large, reflection / interference of stress waves in the load detection unit 2 of each load measuring member 1 can be promoted. As a result, it is possible to achieve early saturation of the stress wave in the load detection unit 2 related to the original load to be measured. As a result, the tensile load or the compressive load can be measured in a wide range of deformation speeds including high-speed deformation. It becomes possible to carry out with higher accuracy.
Further, the load measuring member 1 can further improve the accuracy of the load measurement by making the cross-sectional area of the load detecting unit 2 extremely smaller than the cross-sectional areas of the contact unit 5 and the support unit 6. 3 and the rolling element 4, the displaced contact portion 5 and support portion 6 can be stably guided in the axial direction of the load detection portion 2, so that the cross-sectional area of the load detection portion 2 is made as much as possible. Even if it is made smaller, the influence of the bending moment due to the eccentric load on the load detection unit 2 can be suppressed, and thereby, extremely high measurement accuracy can be realized and the accuracy can be stably maintained.

In the above-described embodiment, the contact portion 5 and the support portion 6 of the load measuring member 1 are made cylindrical, but these contact portions and the support portion have various shapes such as a substantially rectangular shape in a plan view. can do. In this case, for example, when the contact portion and the support portion of the load measurement member are formed in a substantially rectangular cubic shape in plan view, the tube portion is not in contact with the load measurement member and is provided on the outer peripheral surface of the contact portion and the support portion. It is important to provide an inner peripheral surface adapted to the shape of the contact portion and the support portion of the load measuring member in plan view, such as a rectangular tube shape having an inner peripheral surface that conforms.
For the load detection unit, in order to enable highly accurate load measurement even when there is a possibility that an eccentric load may act, such as in the case of a test on a complex structure, Regardless of the shape, it is desirable to have a solid cylindrical shape with uniform load distribution in the cross section.

  Moreover, in the said embodiment, the cross-sectional area of the cross section orthogonal to the axis line of the load detection part 2 of the contact part 5 and the support part 6 is made larger than the cross-sectional area of the cross section orthogonal to the axis line in the load detection part 2. However, the cross-sectional areas of the load detection unit, the contact unit, and the support unit can be set as appropriate. However, as described in detail in the above embodiment, more accurate load measurement can be performed when the cross-sectional area of the load detection unit is smaller than the cross-sectional areas of the contact part and the support part.

Furthermore, in the said embodiment, although it is set as the thing which formed the load measurement member 1 whole, ie, the load detection part 2, the contact part 5, and the support part 6, integrally about the load measurement member 1, At least one of the contact portion and the support portion may be formed integrally with the load detection portion.
In the above embodiment, the load detector 2, the contact portion 5, and the support portion 6 constituting the load measuring device 1 are all made of the same material, that is, having the same elastic modulus and density. However, when the material of each part is different, it is necessary to consider not only the cross-sectional area but also the acoustic impedance when measuring the load. Since acoustic impedance is expressed by the product of material density and stress wave (= elastic wave) propagation velocity, it is important to consider the cross-sectional area multiplied by the density and stress wave propagation velocity when using different materials. . In this case, it is preferable to use a material having a high Young's modulus for the material used for each part.

Moreover, in the said embodiment, although the spherical thing is used as the rolling element 4, the contact part and support part which were displaced by the tensile load or the compressive load other than spherical shape, for example using a cylindrical thing May be arranged so as to be rollable in the direction of guiding in the axial direction of the load detecting portion along the inner peripheral surface of the cylindrical portion. Furthermore, you may use a spherical thing and a cylindrical thing together.
Any rolling element can be used as long as it can be arranged so as to roll freely in the direction in which the displaced contact part and support part are guided along the inner peripheral surface of the cylinder part in the axial direction of the load detection part. In this case, it is preferable that the contact range between the rolling element and the contact portion / support portion be as small as possible in view of the reflectance of the stress wave.

In the above embodiment, eight rolling elements 4 are interposed between the contact portion 5 and the cylindrical portion 3 and between the support portion 6 and the cylindrical portion 3, respectively. As long as the support portion can be stably guided, the number of rolling elements can be set to an arbitrary number. Further, the number of rolling elements between the contact portion and the cylindrical portion may be different from the number of rolling elements between the support portion and the cylindrical portion.
Further, in the above-described embodiment, the arrangement of the respective rolling elements 4 is arranged at equal intervals on the opposite sides of the load measuring member 1, but the displaced contact portion and support portion are arranged on the cylindrical portion. As long as it can be stably and reliably guided along the inner peripheral surface in the axial direction of the load detection unit, it may be provided in any arrangement.

In order to confirm the effect of the present invention, the load measuring device described in the above embodiment (hereinafter referred to as “the present invention example”) and the cylinder portion and the rolling element as in the present invention are not provided as a comparative example. For the load measuring device (hereinafter referred to as “comparative example”), a performance comparison experiment was performed by causing a high-speed collision object to collide with each contact portion.
The collision object was spherical, the weight was 2 kg, and the collision speed was 35 km / h.
Moreover, the thing of the comparative example made the load detection part, the contact part, and the support part into the square pillar shape (cubic shape) of the substantially square shape of planar view with the cross-sectional area of a horizontal cross section substantially the mutually same magnitude | size.
The collision position of the colliding object was a position near the outer peripheral edge on the contact surface of the contact portion in the present invention example, and a corner portion on the contact surface of the contact portion in the comparative example.

In this experiment, first, the unbalance force when a collision object collides (the difference between the cross-sectional force generated at the boundary between the load detection part and the contact part and the cross-sectional force generated at the boundary between the load detection part and the support part) was evaluated. did.
As a result, as shown in FIG. 6, the unbalance force in the example of the present invention is generally lower than that of the comparative example, and the device of the example of the present invention satisfies the balanced state instantly than the device of the comparative example. It was confirmed that it is excellent as a measuring device.
In FIG. 6, the horizontal axis represents the elapsed time after the collision, and the vertical axis represents the difference in cross-sectional force.

Further, in the case of the present invention example, plastic deformation did not occur in each load detection part, but in the case of the comparative example, the localization of the deformation progressed at the joint part between the load detection part and the contact part, and plastic deformation occurred. Was.
As described above, even when an eccentric load acts on the contact portion and a large bending moment is generated in the load detecting portion in the past, the load measuring device of the present invention does not cause plastic deformation and has high accuracy. It was proved that the load measurement can be performed.

DESCRIPTION OF SYMBOLS 1 Load measuring member 2 Load detection part 3 Cylinder part 4 Roller 5 Contact part 6 Support part Ak Sectional area of load detection part At Sectional area of contact part As Sectional area of support part

Claims (4)

A columnar load detector for measuring a tensile load or a compressive load; a contact portion provided on one end side in the axial direction of the load detector to apply a tensile load or a compressive load; and a support portion provided on the other end side. A load measuring member having
A cylindrical portion that covers the load measuring member around the axis of the load detecting portion in a non-contact manner with the load measuring member;
A spherical shape that holds the contact portion and the support portion in the cylindrical portion interposed between the inner peripheral surface of the cylindrical portion and the contact portion and the support portion of the load measuring member facing the inner peripheral surface of the cylindrical portion. Or a plurality of cylindrical rolling elements,
The above-mentioned rolling element is in point contact with each outer peripheral surface of the contact portion and the support portion, and the contact portion and the support portion displaced by the tensile load or the compressive load are arranged along the inner peripheral surface of the cylindrical portion. rollably disposed in a direction for guiding in the axial direction of,
In the load measuring member, the load detecting portion is formed in a columnar shape, and a cross-sectional area of a cross section orthogonal to the axis of the load detecting portion in the contact portion and the support portion is orthogonal to the axis in the load detecting portion. A load measuring device having a cross-sectional area larger than that of the cross section . The load measuring device according to claim 1, wherein the load measuring member is formed integrally with the load detecting unit and at least one of the contact unit and the support unit. The rolling element is claimed in claim 1, characterized in that it is formed by using a material different densities and material of the contact portion and the support portion, the load measuring device according to claim 2.   4. The load measuring device according to claim 1, wherein the load measuring device is a load measuring device for measuring an impact load.

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