JP2753483B2 - Load transducer for detecting vertical force acting on road surface of automobile - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a load transducer, and more particularly, to a pressure receiving plate which forms a part of a road surface of an automobile for detecting a vertical force acting on the road surface of the automobile when the automobile travels. A plurality of strain gauges are attached to a strain generating body that is elastically deformed when a load is applied through the pressure receiving plate, and detects a vertical force acting on the road surface of the automobile. The present invention relates to a load converter.

[0002]

2. Description of the Related Art The motion of a motor vehicle is mostly determined by the force generated between a tire and a road surface during running. Therefore, measuring the vertical force, the front-rear direction force, and the lateral force acting on the traveling road surface is extremely significant in knowing the motion state of the vehicle. 9 and 10 are prototypes made by the present inventors, and schematically show the configuration of a device for measuring a lateral force acting on a road surface when an automobile runs (hereinafter referred to as a “road surface force measurement device”). It is the top view and front view shown.

In FIG. 1, reference numeral 1 denotes a pressure receiving plate, which corresponds to a running road surface of an automobile at the time of measurement. Reference numeral 2 denotes a load support plate, whose lower end is firmly fixed on a support base 3 as a support fixedly supported in the ground, and whose upper end is firmly fixed to the pressure receiving plate 1. Reference numeral 4 denotes a laterally long fixing plate, which fixedly supports a fixed side of a narrow lateral force detecting strain generating portion 1b formed between the extension portion 1a of the pressure receiving plate 1 and the fixing plate 4. is there.

A strain gauge SG whose sensitive axis is oriented at 45 ° and 135 ° with respect to the lateral force measurement direction indicated by reference symbol Y is adhered to the lateral force detecting strain generating portion 1b. Thus, it is possible to detect the shear strain generated in the strain generating portion 1b when a lateral force is applied. A road surface acting force measuring device having such a configuration is
The length in the traveling direction is 0.5 m per piece,
By arranging them in parallel, measurement is possible in a total section of 2 m.

[0005] The operation of the thus-configured road surface force measuring device will be described. When an automobile (not shown) travels in the traveling direction indicated by the symbol X and a wheel is mounted on the pressure receiving plate 1, the wheel load is applied to the load support plate 2 via the pressure receiving plate 1. Further, when the vehicle travels on the pressure receiving plate 1, lateral force generated by the state of the vehicle alignment, suspension, tires and the like is transmitted to the strain generating portion 1b via the extension portion 1a of the pressure receiving plate 1, and the strain is generated. A shear strain is caused in the portion 1b.

Therefore, the sense axis is 4
One of the strain gauges SG (not shown) bonded to the strain generating portion 1b at angles of 5 ° and 135 ° expands to increase the resistance value, and compresses the other to decrease the resistance value.
Since a Wheatstone bridge circuit (hereinafter simply referred to as a “bridge circuit”) is formed by these strain gauges SG, by applying a bridge voltage to an input terminal of the bridge circuit, the output terminal thereof applies a voltage to each pressure receiving plate 1. A strain output corresponding to the applied lateral force can be obtained. Incidentally, the lateral force can be obtained by adding the outputs of the respective bridge circuits formed by the strain gauges provided in the respective strain generating portions 1b.

[0007] Although the road surface force measuring device constructed and operated as described above generally obtains satisfactory results in measuring the lateral force, the vertical force is measured by using a conventional load converter. There are various problems to be overcome in order to measure with high accuracy in a short section on the side. That is, when measuring the vertical direction with such a vertical road surface force measuring device, an extremely wide response frequency range including a DC component (DC to several hundred Hz) while ensuring sufficient sensitivity.
In many cases, the force in the front-rear direction (the direction indicated by the symbol X) and the lateral force act simultaneously,
It is required that crosstalk is extremely small,
Sufficient strength and rigidity must be ensured.

To obtain a high response frequency, a load converter using a piezo element is suitable, but this type has a weak point that there is no response to a DC component. Therefore, in the above-described road surface acting force measuring device, a strain gauge type transducer having a responsiveness to a DC component is used. To increase the natural frequency of a one-degree-of-freedom vibration system, first, reduce the mass of the movable part as much as possible, and second, increase the spring constant of the system as much as possible while securing the required sensitivity. Must be achieved while sufficiently suppressing crosstalk.

Regarding the first point, the weight is reduced by using a duralumin thin plate for the pressure receiving plate 1 and a large number of duralumin load support plates 2 are connected to the support frame 3 at a fine pitch. This can be dealt with by using an extremely lightweight movable part having high rigidity, low crosstalk, and sufficient strength and rigidity. Regarding the lateral force, of the second point, regarding the lateral force, the strain generating portion 1b has an integral structure with the measurement surface (pressure receiving surface), and the length of the strain generating portion 1b is shortened as much as possible, and at the vicinity of the strain generating portion 1b. By devising a method such as providing the load supporting plate 2 made of duralumin, it is possible to obtain a very high spring constant while securing necessary sensitivity and low crosstalk.

However, with respect to the vertical force, the cross-talk is sufficiently suppressed even if a lateral force or a front-rear direction force acts, a sufficient sensitivity is secured, and a wide response frequency range including a DC component is provided. It is difficult to secure high sensitivity and rigidity. For example, the above-mentioned problem will be described for a load converter as shown in FIGS. 7 and 8 which is conventionally used.

FIG. 7 is a front view of a conventional load converter, and FIG. 8 is a right side view thereof. In this figure, the conventional load converter 6 has a thin overall shape, and through holes 7,..., 8,.
, A total of eight holes are drilled, and the middle part sandwiched between the through holes 7... 8 is made thin to form a strain generating part 9. Since a compressive load acts on each of two strain gauges, that is, in this case, the load transducer 6, a strain gauge SG1 for detecting the compressive strain is applied to the surface.
And SG3, and strain gauges SG2 and SG4 for detecting tensile strain based on Poisson's ratio are respectively attached by an adhesive, so that the load applied through the pressure receiving plate 1 can be detected by the strain gauges SG1 to SG4. Have been.

In the load converter 6, the rigid body portion in which the through holes 7 are formed is referred to as a load introducing portion 10 and the through holes 8 are formed.
Are referred to as load supporting portions 11. However, when trying to detect the vertical force in the road surface acting force measuring device using the above-described conventional load converter, the following problem occurs.

First, in this conventional load converter,
If an attempt is made to increase the response frequency by increasing the stiffness, the obtained distortion output (sensitivity) becomes small, which causes a problem that the noise resistance is poor. On the other hand, if a large strain output is to be obtained as in the case of a diaphragm-type load transducer, there arises a problem that the response frequency is reduced.

Second, since the difference between the working stress and the breaking stress is small, it is not possible to apply an overload that is much larger than the rated load. In other words, it is sufficient to increase the capacitance. However, in such a case, a new problem arises that the measurement stress (resolution) decreases because the working stress level naturally decreases.

Third, when a load is not applied along the direction of the sensitive axis of the load transducer 6, that is, when an eccentric load is applied to the load introducing unit 10, an accurate load cannot be detected. Therefore, it is difficult to suppress crosstalk.
Fourth, since the difference between the working stress of the load transducer and the breaking stress (extreme strength) of the strain generating element cannot be made large, the material of the strain generating element necessarily has high strength, that is, high tensile strength or tensile strength. A high-pressure material (special steel or the like) having a high pressure must be used, which causes a problem that the material cost, the processing / processing cost increases, and the cost increases.

[0016]

SUMMARY OF THE INVENTION The present invention has been made to solve all the problems of the above-mentioned conventional load converter. The first object of the present invention is to provide a DC converter while ensuring sufficient sensitivity and resolution. An object of the present invention is to provide a load transducer having an extremely wide response frequency range including components. A second object of the present invention is to provide a load transducer capable of improving the resolution while significantly improving the safety by making the ratio between the working stress and the breaking stress extremely large.

A third object of the present invention is to provide a load converter capable of accurately detecting a vertical force even when receiving an eccentric load or a lateral load and having extremely little crosstalk. A fourth object of the present invention is to provide a load converter which does not necessarily need to use a high-grade material having a large tensile strength or a high pressure, can use an inexpensive material, and can realize a reduction in price accordingly. Is to provide.

[0018]

SUMMARY OF THE INVENTION In order to achieve the first, second, and fourth objects, the present invention provides a vehicle for detecting a vertical force acting on a road surface of a vehicle when the vehicle travels. A plurality of load transducers are provided so as to support a pressure receiving plate forming a part of the traveling road surface, and a strain gauge is attached to a strain generating body which elastically deforms when a load is applied through the pressure receiving plate. And an upper end portion and a lower end portion of the strain body in a load application direction, which are provided with rigid attachment portions which are respectively attached to the pressure receiving plate and a support member arranged to face the pressure receiving plate. A first strain-generating portion having a thin and small cross-sectional area in the middle portion of the body and having a small length along the load application direction, and one end being connected in series with one end of the first strain-generating portion; It is provided continuously, has a cross-sectional area sufficiently larger than the first strain generating portion, and applies a load. A second strain generating portion having a sufficiently large length in the direction, and a cross-sectional area sufficiently larger than the first strain generating portion so as to surround the first and second strain generating portions. And the length in the load application direction is set to be sufficiently larger than the total length of the first and second strain generating portions, and the other end of the first strain generating portion and the other of the second strain generating portion. A third strain-generating portion having an end connected integrally is provided, and the first strain-generating portion includes:
A plurality of strain gauges are attached so that a strain in a load application direction can be detected, and an electric signal corresponding to the applied load is obtained by the strain gauge.

In order to achieve the first, second, and fourth objects, the present invention provides a method for detecting a vertical force acting on a road surface of a vehicle when the vehicle is running. A plurality of pressure transducers are provided so as to support the pressure receiving plate forming the part, and a strain gauge is attached to a strain-generating body that elastically deforms when a load is applied through the pressure receiving plate, At the upper end and the lower end in the load application direction of the strain body, rigid attachment portions are provided, each of which is attached to the pressure receiving plate and a support body disposed to face the pressure receiving plate, and an intermediate portion of the strain body. Forming two slits that are symmetrical with respect to the center line of the strain body and penetrate from one surface side to the other surface side of the strain body, so that a cross-sectional area outside the two slits is formed. And a third strain-generating portion having a large diameter A second strain-generating portion having a large cross-sectional area is provided in the portion, and the first strain-generating portion having a smaller length in the load application direction and a smaller dimension in the width direction orthogonal thereto than the second strain-generating portion. A distorted portion, wherein the first distorted portion and the second
One end of the strain generating portion is connected in series, and the other end of each of the first and second strain generating portions is connected to the third strain generating portion, respectively. A plurality of strain gauges capable of detecting a strain in a load application direction are attached thereto, and an electric signal corresponding to the applied load is obtained by the strain gauge.

According to the present invention, in order to achieve the first to fourth objects, the second strain generating portion near the first strain generating portion is provided with the third strain generating portion. A transverse vibration preventing beam having flexibility in a load application direction and rigidity in a direction perpendicular to the load application direction is provided so that the spaces are connected to each other.

According to the present invention, in order to attain the third object, the first strain generating portion is formed at a center in a width direction and a thickness direction of the strain generating body. It is a feature.

According to the present invention, in order to attain the third object, a pair of the mounting portions provided at upper and lower ends of the strain body and the third strain generating portion are provided. Further, a constricted portion is provided by forming a groove having a predetermined depth from the side peripheral surface toward the central axis.

In order to achieve the first to fourth objects, the present invention forms a part of an automobile traveling road surface for detecting a vertical force acting on the automobile traveling road surface when the automobile travels. A load transducer provided with a strain gauge attached to a strain-generating body elastically deformed when a load is applied through the pressure-receiving plate, the strain transducer being provided with a plurality of pressure-receiving plates. At the upper end and lower end of the body in the load application direction, provided are rigid attachment portions respectively attached to the pressure receiving plate and a support disposed to face the pressure receiving plate, and an intermediate portion of the strain body, Two parallel slits penetrating from one surface side to the other surface side of the flexure element are formed at positions symmetrical with respect to the center line of the flexure element, and a non-slit portion having a predetermined size is formed between the parallel slit and the parallel slit. A parallel slit extending through the end and its end Together form a concave slit communicating said thin between the bottom surface of both the counterbore by bored counterbore having a predetermined depth from both sides in the non-slit portion 2
Forming two first strain-generating portions, and having the two first strain-generating portions have sensing axes in directions of 45 ° and 135 ° so that a shear strain can be detected with respect to a center line of the strain-generating body. A plurality of strain gauges are attached in such a manner that an electric signal corresponding to the applied load is obtained by the strain gauge.

[0024]

The load converter for detecting a vertical force acting on the road surface of the vehicle constructed as described above (hereinafter simply referred to as "the load converter") is provided on a pressure receiving plate which forms a part of the road surface of the vehicle. The mounting portion on the upper end side is mounted, and the mounting portion on the lower end side is mounted on the support facing the pressure receiving plate at a predetermined interval below the pressure receiving plate. As a result, the mounting portion has extremely high rigidity in the vertical direction. A structure is formed. When a vertical force at the time of traveling of the vehicle is applied to the load introducing portion (the upper end mounting portion) of the strain body via the pressure receiving plate, the vertical force is transmitted through a narrow portion having a small cross-sectional area. Third with great rigidity
Is transmitted to the strain-generating part.

The vertical force is also split and transmitted to the second strain generating portion, whose upper end is formed integrally with the third strain generating portion. A lower end and an upper end of the second strain generating portion are integrally connected, and a lower end of the second strain generating portion is also connected to the first strain generating portion integrally formed with the third strain generating portion via the second strain generating portion. Since the applied load is transmitted, the first strain generating portion generates a compressive strain in the vertical direction corresponding to the applied load, and generates a tensile strain in the horizontal direction in accordance with the Poisson's ratio.

The amount of compressive strain is determined by the ratio of the vertical length (length of the slit) of the second strain-generating portion to the vertical length of the first strain-generating portion. Because the strain is enlarged (amplified), the strain sensitivity is high, the noise resistance is improved, and the applied load is supported by the third flexure element having extremely low flexibility, in other words, high rigidity. , Has an extremely wide response frequency range including DC components,
Further, the difference between the working stress and the breaking stress can be increased, and the structure can sufficiently withstand an overload.

Also, the second strain generating portion in the vicinity of the first strain generating portion has flexibility in the load application direction so that the second strain generating portion and the third strain generating portion are connected to each other. In the direction orthogonal to the load application direction, a rigid lateral run-out preventing beam is provided, and an eccentric load, a lateral load, and a rotational moment act on the load introducing portion to cause the first vibration.
This prevents the strain generating portion from being carelessly bent or twisted, is less susceptible to the eccentric load, the lateral load, and the like, and can accurately detect only the vertical force. This means that the beam works effectively while keeping the crosstalk extremely small.

A groove having a predetermined depth from the side peripheral surface toward the center axis is formed between the pair of mounting portions provided at the upper and lower ends of the strain body and the third strain portion. By providing the constricted portion, even if an eccentric load (non-uniform distributed load) or a lateral load is received, this is absorbed (concentrated) by the constricted portion, and further rigidized by the third strain generating portion having higher rigidity. The light is dispersed substantially uniformly and transmitted to the second strain generating portion, so that the influence of the unbalanced load or the like on the detection of the vertical force is suppressed to an extremely small value.

[0029]

Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 and 2 are a front view and a right side view showing an embodiment of a load transducer for detecting a vertical force acting on a road surface of an automobile according to the present invention. In the figure, reference numeral 12 denotes a strain-generating body having a substantially rectangular plate shape whose overall shape is elongated in a load application direction (vertical direction in the figure), and the pressure receiving member as an object to be measured is provided at both ends in the load application direction. A mounting portion on the upper end side for mounting on the plate 1 and the support table 3 as the other object to be measured
Is formed at the lower end.

In this case, a plurality of (four in this embodiment) female screw holes 13 for mounting the present load converter are formed on the pressure receiving plate 1 or a member integral with the pressure receiving plate 1. A plurality (four in this case) of mounting bolt insertion holes 14 for mounting the present load converter on 3 or an integral member thereof are formed. The portion of the mounting portion where the female screw hole 13 is formed is a rigid portion that is formed thick in both the vertical direction and the radial direction and does not substantially deform. Shall be referred to.

On the other hand, the portion of the mounting portion on the lower end side where the mounting bolt insertion hole 14 is formed is also formed as a rigid portion which is thick in both the vertical direction and the radial direction and does not substantially deform. Here, it is referred to as a load supporting portion 16. The intermediate portion of the flexure element 12 is symmetrical with respect to the center line O of the flexure element 12, and extends from one side (the front side in FIG. 1) to the other side (in FIG. 1). Two first slits 17 and 18 penetrating through (on the back side) are formed.

At the lower ends of the two first slits 17 and 18, the width of the slit is widened toward the center line.
The expanded slits 17 and 18 have second slits 19 and 20 extending downward through a thin non-slit portion therebetween. The non-slit portions are thin and flexible in the direction of the center line O, but are thick and rigid in the lateral direction, and are the beams 21 and 22 for preventing lateral vibration.
By forming the two first and second slits 17, 18 and 19, 20, a third strain-generating portion 23 is provided outside thereof.

Further, a second strain generating portion 24 is provided at a portion sandwiched by the first slits 17 and 18, and a second strain generating portion is provided at a portion sandwiched by the second slits 19 and 20. A first strain generating section 25 is provided in series with one end of the first section 24. The method of forming the first strain-generating portion 25 is as follows. First, in order to reduce the width of the first strain-generating portion 25, through holes 26, 27 reaching from the one surface side to the other surface side with a drill having a radius r. And then perform reaming if necessary.

Next, as shown in FIG. 2, counterbore holes 30 and 31 having a diameter D are drilled from one surface side and the other surface to the center by, for example, a milling machine, and a thickness t is formed at the center. The first thin strain-generating portion 25 is formed. Then the first
Slits 17 and 18 and second slits 19 and 20
For example, by forming sequentially by wire electric discharge machining, the first strain generating portion 25 shown in FIGS. 1 and 2 is completed.

Between the load introducing part 15 of the strain body 12 and the third strain part 23, and between the load supporting part 16 and the third strain part 2
3, narrow portions 28 and 29 each having a small diameter and a circular cross section are formed. On one surface side and the other surface side of the first strain generating portion 25, strain gauges SG1 and SG3 for compressive strain detection are attached with the sense axis directed toward the center line O, and the sense axis is aligned with the center line O. The strain gauges SG2 and SG4 for detecting tensile strain are attached in a direction perpendicular to the direction.

Next, the mounting of the present load converter having the above-described configuration to the above-mentioned road surface acting force measuring device and the operation of the present load converter will be described. First, a method of attaching the present load transducer to the road surface acting force measuring device will be described with reference to FIGS. 9 and 10. When the load supporting plate 2 shown in FIG. Many are arranged.

Then, four mounting bolts (not shown) inserted into the pressure receiving plate 1 or a member integral with the pressure receiving plate 1 are strongly screwed into four female screw holes 13 formed in the load introducing portion 15, whereby The strain body 12 is fixed to the pressure receiving plate 1. On the other hand, the load support portion 1 is inserted into the female screw hole formed in the support base 3 or a member integral with the support base 3 of the road surface force measuring device.
The strain body 12 is fixed to the support 3 by screwing in mounting bolts (not shown) inserted into the four mounting bolt insertion holes 14 formed in 6. Similarly, a plurality of other load transducers are mounted on the road surface force measuring device.

When the traveling vehicle is mounted on the pressure receiving plate 1 supported by the load converters in this manner, the wheel load of the vehicle is loaded on the pressure receiving plate 1, so that the vehicle is disposed at a predetermined interval. Each of the load converters receives a part of the wheel load as an applied load from the load introducing unit 15 via the pressure receiving plate 1. The load (compression load) applied from the load introducing unit 15 is transmitted to the third strain generating unit 23 and the second strain generating unit 24 via the constricted portion 28. Since the upper end is continuously provided to the second strain generating portion 24 and the lower end is continuously provided to the third strain generating portion 23, a part of the load is also transmitted to the first strain generating portion 25. You.

Since the load supporting portion 16 is fixedly supported on the support base 3 at the lower end of the flexure element 12, a reaction force of the opposite direction and the same magnitude is applied to the above-mentioned applied load via the constricted portion 29. And transmitted to the lower portion of the third strain generating section 23. Accordingly, a portion (L1 + L) of the third strain generating portion 23 where the slits 17 to 20 are formed by the load applied to the strain generating body 12.
2) The amount of strain caused by compression is equal to the amount of combined strain of the second strain generating portion 24 and the first strain generating portion 25.

However, the first strain-generating portion 25 is extremely thin and formed to be narrow, while the second strain-generating portion 24 is thick and sufficiently wide. Therefore, the compressive strain generated in the section of the slit (L1 + L2) is substantially concentrated on the first strain generating portion 25. This can be explained with reference to a model diagram in FIG. 3 in which the elastic coefficients of the first to third strain generating portions of the present load transducer are equivalently represented.

That is, the pressure receiving plate 1 is
Above, it is equivalent to being elastically supported via a strain body (the present load transducer) 12. The elastic modulus k1 of the first strain generating portion 25 is extremely small, whereas the elastic modulus k2 of the second strain generating portion 24 and the elastic modulus k3 of the third strain generating portion 23 are small.
Is set very large.

Therefore, the elastic coefficient of this vibration system is k1≪
Since k2 and k1≪k3, and k1 and k3 are in a parallel connection relationship, k ≒ 2 × k3, and the third strain generating portion 23 substantially supports the pressure receiving plate 23, In other words, since the spring constant (elastic coefficient) of the vibration system can be made extremely large, a load converter having an extremely wide response frequency range including a DC component can be obtained.

In the strain detection, the strain amount (L1 / L2) times the strain amount of the third strain generating portion 23 between the slits 17 to 20 is calculated by the first strain generating portion 2.
5, even if the elastic modulus of the third strain generating portion 23 is large, a large amount of strain can be obtained. In other words,
The strain gauges SG1, SG2,... Attached to the first strain-generating portion 25 provide a large strain output while realizing an increase in the natural frequency and an increase in the difference between the working stress and the breaking stress, thereby significantly increasing the resolution. It can be improved.

Even if the load transducer shown in FIGS. 1 and 2 receives an eccentric load (unevenly distributed load), it is absorbed (concentrated) by the constricted portion 23 and further substantially rigid. Since the upper portion of the third strain generating portion 23, which can be regarded as a portion, is substantially uniformly dispersed and transmitted to the third strain generating portion 23 on the side of the slits 17 to 20, the influence of the above-described eccentric load is greatly reduced. Can be reduced.

Further, on the side of the second strain generating portion 24 close to the first strain generating portion 25 of the present load converter, the space between the second strain generating portion 24 and the third strain generating portion 23 is connected to each other. Since a thin beam is provided in the direction of the center line O (in the direction in which the load is applied) to have good flexibility, and a thick beam is provided in a direction perpendicular to the center line O to provide a lateral vibration prevention beam having a large rigidity. Even if the lateral load is mixed in the vertical force, the lateral load is the beam 2
2 functions to block, the vertical force can be accurately detected without being affected by the lateral load.

FIG. 4 is a characteristic diagram of the present load transducer.
Shown in This characteristic diagram shows the non-linear characteristic of the present load transducer having a rated capacity of 5 ton. The non-linear characteristic (the value of the maximum output deviation expressed as a percentage of the rated output) is 0.
This indicates that a good result of 025% RO was obtained. On the other hand, the non-linearity characteristics of the conventional load transducer shown in FIGS. 7 and 8 are as shown in FIG. 5, and the non-linearity is about 0.05% RO, and especially the load The non-linearity at the time of decrease is large, and it can be seen that the load transducer according to the present invention has much better characteristics.

Further, since the load transducer according to the present invention can reduce the strain (stress) generated in the third strain generating portion 23 compared with the conventional one, a high precision using a region where the elastic properties of the material is good can be achieved. A simple load transducer can be manufactured. This means that even a low-strength material having a small range in which the load is proportional to the strain (stress) (that is, a narrow elastic deformation range) can be used. Inexpensive ones are sufficient, processing costs, heat treatment costs, and the like are reduced, and thus an inexpensive load transducer can be provided.

It should be noted that the present invention is not limited to the above-described embodiment, and can be variously modified and implemented without departing from the gist of the present invention. For example,
FIGS. 9 and 1 show a road surface force measuring device to which the present invention is applied.
However, the present invention is not limited to the one shown in FIG. 0, but it can be applied to any device having any type and configuration as long as it measures the vertical force on the traveling road surface.

The present load converter is not limited to the first embodiment shown in FIGS. 1 and 2, but may be one shown in FIG. The flexure element 39 shown in FIG. 6 differs from that shown in FIGS. 1 and 2 in the configuration of the first flexure section. More specifically, the first flexure sections 37 and 38 have two It is provided in some places, and differs in that the method of detecting strain is a method of detecting shear strain. Therefore, the same reference numerals are given to the same parts as those in the embodiment shown in FIGS. 1 and 2, and the description of the overlapping configuration and operation is omitted.
The different parts will be mainly described.

That is, two parallel slits 17 penetrating from one surface (front surface side) to the other surface (back surface side) at a position symmetrical with respect to the center line O are provided at an intermediate portion of the flexure element 39. , 1
8 and parallel slits are extended between the parallel slits 17 and 18 through non-slit portions 35 and 36 of a predetermined size (dimensions required for forming the strain-generating portion). The second as a concave-shaped slit by communicating with each other
Is formed.

The non-slit portions 35 and 36 are provided with counterbore holes 33 with a certain depth from one side and the other side.
By drilling 34, two thin first strain-generating portions 37, 38 are formed between the bottom surfaces of the counterbore holes 33, 34. Strain gauges SG1 to SG4 (provided that SG3, SG3 are set) with their sensitive axes oriented in directions of 45 ° and 135 ° with respect to the center line O of the strain body 39 on the first strain generating portions 37, 38, respectively.
G4 does not appear in the drawing).

The load converter of the second embodiment shown in FIG. 6 configured as described above has the same basic operation as that of the first embodiment, except that the applied load is changed in the form of a shear strain. Therefore, the non-slits 35, 36 and the first strain-generating portions 37, 38 function to mechanically prevent lateral vibration against lateral load and eccentric load. Even if the strain generating portions 37 and 38 are slightly deformed by receiving compressive and tensile forces in the left and right directions, a bridge circuit is formed by the four strain gauges SG1 to SG4 to electrically cancel the strain in the transverse direction. Therefore, the effects of the unbalanced load and the lateral force can be almost eliminated.

[0053]

As described in detail above, according to the present invention, an extremely wide response frequency range including a DC component (for example, DC to several hundred Hz) while securing sufficient distortion sensitivity.
The resolution can be greatly improved while significantly improving the safety by greatly increasing the ratio of the used stress to the fracture stress, and the vertical direction even when subjected to an eccentric load, lateral load, or moment Forces can be separated and detected accurately, so that crosstalk is extremely small.Furthermore, there is no need to use high-grade materials with high tensile strength and pressure, and low costs can be realized by using inexpensive materials. To provide a load converter capable of detecting a vertical force on a road surface of a vehicle generated during running of a vehicle in a wide range and accurately from a low speed range to a high speed range. Can be.

[Brief description of the drawings]

FIG. 1 is a front view showing a first embodiment of the present load converter according to the present invention.

FIG. 2 is a right side view of the embodiment shown in FIG.

FIG. 3 is a drawing modeling the first embodiment.

FIG. 4 is a non-linear characteristic diagram of the load converter according to the first embodiment of the present invention.

FIG. 5 is a non-linear characteristic diagram of a conventional load converter.

FIG. 6 is a front view illustrating a configuration of a load converter according to a second embodiment of the present invention.

FIG. 7 is a front view showing a configuration of a conventional load converter.

FIG. 8 is a right side view showing the configuration of the conventional load converter shown in FIG.

FIG. 9 is a plan view schematically showing a configuration of a road surface acting force measuring device prototyped by the present inventors.

FIG. 10 is a front view schematically showing the configuration of the device shown in FIG.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 pressure receiving plate 2 load support plate 3 support base 4 fixing plate 1a extension portion 1b lateral force detecting strain generating portion 12 strain generating body 13 female screw hole 14 mounting bolt insertion hole 15 load introducing portion 16 load supporting portion 17, 18 first Slits 19, 20 Second slits 21, 22 Beam for preventing lateral shake 23 Third strain generating part 24 Second strain generating part 25 First strain generating part 26, 27 Through hole 28, 29 Narrow part 30, 31 Counterbore hole 32 Second slit 33,34 Counterbore hole 35,36 Non-slit part 37,38 First strain-generating part 39 Flexure element

Continuation of the front page (56) References JP-A-7-198462 (JP, A) JP-A-5-60624 (JP, A) JP-A-1-94234 (JP, A) Atsuo Hirota, "High response for automobiles Prototype of Force Plate ", Proceedings of the 72nd Annual General Meeting (1), Japan Society of Mechanical Engineers, March 1995, 366-367

Claims (6)

(57) [Claims] A plurality of pressure receiving plates are provided to support a pressure receiving plate forming a part of a vehicle traveling road surface for detecting a vertical force acting on the vehicle traveling road surface when the vehicle travels. A strain transducer attached to a strain body that elastically deforms when a load is applied thereto, wherein the pressure receiving plate and the pressure receiving plate are provided at upper and lower ends of the strain body in a load application direction. A rigid attachment portion attached to each of support members disposed opposite to each other, and having a thin and small cross-sectional area at an intermediate portion of the strain body and having a small length along a load application direction. And a first strain-generating portion having one end connected to one end of the first strain-generating portion in series and having a cross-sectional area sufficiently larger than that of the first strain-generating portion, and in a load application direction. A second strain generating portion having a sufficiently large length; It has a cross-sectional area sufficiently larger than the first strain-generating portion so as to surround the strain-generating portion, and the length in the load application direction is sufficiently longer than the total length of the first and second strain-generating portions. A third strain-generating portion, which is set to be large and is formed by integrally connecting the other end of the first strain-generating portion and the other end of the second strain-generating portion; A plurality of strain gauges are attached so as to detect a strain in a load application direction, and an electric signal corresponding to the applied load is obtained by the strain gauge. Load transducer for vertical force detection. 2. A plurality of pressure receiving plates, which form a part of a vehicle traveling road surface, are disposed to detect a vertical force acting on the vehicle traveling road surface when the vehicle travels. A strain transducer attached to a strain body that elastically deforms when a load is applied thereto, wherein the pressure receiving plate and the pressure receiving plate are provided at an upper end and a lower end in a load application direction of the strain body. A rigid attachment portion attached to each of the support members disposed opposite to each other is provided, and an intermediate portion of the flexure element is symmetric with respect to a center line of the flexure element, 2 penetrating from one side to the other side
By forming three slits, a third strain-generating portion having a large cross-sectional area is provided outside the two slits, and a second strain-generating portion having a large cross-sectional area is provided at a portion sandwiched between the slits. In addition to the first strain-generating portion, the first strain-generating portion is provided with a thin first strain-generating portion having a smaller length in the load application direction and a smaller dimension in the width direction orthogonal to the second strain-generating portion. (2) connecting one end of the strain-generating portions in series, and connecting the other ends of the first and second strain-generating portions to the third strain-generating portion, respectively; A plurality of strain gauges capable of detecting a strain in a load application direction are attached to the portion, and the strain gauges are configured to obtain an electric signal corresponding to the applied load. Load transducer for detecting directional force. 3. The flexibility in the load application direction is provided so that the second strain generating portion near the first strain generating portion is connected to the third strain generating portion. 3. A load transducer for detecting a vertical force acting on a road surface of an automobile according to claim 1, wherein a beam for preventing lateral vibration having rigidity is provided in a direction perpendicular to the direction in which the load is applied. . 4. The vehicle traveling road surface according to claim 1, wherein the first strain generating portion is formed at a center portion in a width direction and a thickness direction of the strain generating member. Acting load transducer for vertical force detection. 5. A groove having a predetermined depth from a side peripheral surface toward a center axis between a pair of the attaching portions provided at upper and lower ends of the strain body and the third strain portion. 3. A load converter for detecting a vertical force acting on a road surface of an automobile according to claim 1, wherein the constricted portion is provided by forming a concave portion. 6. A plurality of pressure receiving plates forming a part of a vehicle traveling road surface are disposed to detect a vertical force acting on the vehicle traveling road surface when the vehicle travels. A strain transducer attached to a strain body that elastically deforms when a load is applied thereto, wherein the pressure receiving plate and the pressure receiving plate are provided at an upper end and a lower end in a load application direction of the strain body. A rigid attachment portion attached to each of support members disposed opposite to each other, and a surface of the strain body at an intermediate portion of the strain body at a position symmetrical with respect to a center line of the strain body. Two parallel slits penetrating from one side to the other side are formed, and a parallel slit is extended between the parallel slits through a non-slit portion having a predetermined dimension and the ends thereof are communicated with each other. A concave slit is formed and the non-slip Forming two thin first strain-generating portions between the bottom surfaces of the two counterbore holes by drilling a counterbore of a predetermined depth from both sides of the portion; A plurality of strain gauges are attached with their sensitive axes oriented in directions of 45 ° and 135 ° so that a shear strain can be detected with respect to the center line of the strain element, and an electric signal corresponding to the applied load is applied by the strain gauge. A vertical force detecting load transducer acting on the road surface of an automobile, characterized in that it is configured to obtain the following.