JP2000028423A - Load measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a load measuring device wherein a load is measured with precision, no calibration is needed at assembly to a car, the assembly is easy and the replacement at maintenance is facilitated. SOLUTION: A magnetostrictive material 6 is melt-sprayed around a body part 1 into one body. The magnetostrictive material 6 is for detecting a distortion of the body part 1, which changes its magnetic characteristics (inductance and loss resistance) according to the distortion of the body part 1. With a tip end (free end) of a cantilevered leaf spring holding pin 11 supported by a load measurement part A, a load is directly measured by the load measurement part A.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a load measuring device used for measuring a loaded weight of a truck and the like, and more particularly to a load capable of improving workability in assembling to a vehicle and improving maintenance in the event of a failure. It relates to a measuring device.

[0002]

2. Description of the Related Art Conventionally, as a load measuring device of this kind,
One described in Japanese Patent Application Laid-Open No. Hei 8-254456 is known. In this load measuring device, a sensing element for load measurement is built in the shackle pin that supports the leaf spring (leaf spring) of the truck, and the load is indirectly measured by measuring the strain of the shackle pin with the sensing element for load measurement. Is what you do.

[0003]

However, in the above-mentioned conventional load measuring device, since the sensing element for load measurement is built in the shackle pin, the shackle pin must be replaced together with the shackle pin at the time of failure, making maintenance difficult. There is a problem that is. Also, when assembling the load-measuring sensing element into the shackle pin, it must be press-fitted, causing distortion in the load-measuring sensing element.
There is a problem that it is necessary to perform calibration after assembly.
Further, since the load is indirectly measured by measuring the strain of the shackle pin with the load measuring sensing element, there is a complaint that good measurement accuracy cannot be obtained.

[0004] The present invention has been made in view of the above circumstances, and an object of the present invention is to enable accurate load measurement and to eliminate the need for calibration when assembling to a vehicle, and to assemble easily. Another object of the present invention is to provide a load measuring device which can be easily replaced during maintenance.

[0005]

According to a first aspect of the present invention, there is provided a load measuring device provided on a leaf spring holding pin for holding a leaf spring for measuring a vehicle loading weight, wherein the leaf spring fixing pin is provided. Is provided in a cantilever shape, and a load measuring unit for supporting the leaf spring fixing pin is provided opposite to the tip of the leaf spring fixing pin. According to the first aspect, the load is directly measured by the load measuring unit by supporting the tip (free end) of the cantilevered leaf spring holding pin by the load measuring unit.

According to a second aspect of the present invention, the load measuring section includes a main body section distorted by a load, a screw section provided at an upper portion of the main body section, a load supporting section provided at a lower section of the main body section, A magnetic material that is sprayed on the outer peripheral surface of the main body and has a magnetic property that changes in accordance with the distortion of the main body, and a magnetic material that is disposed on the outer periphery of the magnetic material and that changes the magnetic property of the magnetic material with an electrical impedance. A conversion element for converting the change into a change, a temperature compensation circuit connected to the conversion element, for compensating the change in the impedance based on the temperature change, and detecting the change in the impedance based on the distortion of the main body; Measuring means for measuring distortion. According to the second aspect, when distortion occurs in the main body due to the load received by the load supporting portion, the change in the magnetic characteristics of the magnetic material according to the distortion of the main body is determined by the conversion element. The impedance is converted to a change in electrical impedance, and the temperature compensation circuit compensates for the change in impedance due to temperature change, and the measuring unit converts the impedance into distortion of the main body to measure the load applied to the main body. I do.

According to a third aspect of the present invention, the main body and the magnetic material are connected to each other.
Linear expansion coefficient difference is 1 × 10^-6K^-1Features are
And According to the third aspect, the main body and the magnetic material are
The difference in linear expansion coefficient is 1 × 10^-6K ^-1By
The magnetic properties (inductance) of the magnetic material
And loss resistance) as much as possible, resulting from temperature changes.
The measurement error (temperature drift) is reduced as much as possible.

A fourth aspect of the present invention is characterized in that the conversion element is a coil wound around an outer periphery of a magnetic material. According to the present invention, the variation in the distortion between the magnetic material and the main body is achieved by converting a change in the magnetic characteristics of the magnetic material into a change in the electrical impedance by means of a coil wound around the outer periphery of the magnetic material. And the distortion is detected with high accuracy.

According to a fifth aspect of the present invention, the main body is cylindrical.
It is characterized by being cylindrical, prismatic or prismatic. The shape of the main body is preferably a column, a cylinder, a prism, or a prism. Thereby, the manufacture of the main body is easy, and the magnetic material is easily sprayed on the outer peripheral surface of the main body.

According to a sixth aspect of the present invention, a leaf spring holding bracket is provided with a base end of a leaf spring holding pin, and a distal end of the leaf spring holding pin is formed on the leaf spring holding bracket. A screw hole that is loosely fitted in the leaf spring holding pin hole and that is screwed into the screw portion of the load measuring unit from the upper surface of the leaf spring holding bracket toward the leaf spring holding pin hole is formed in a vertical direction. A nut for fixing the screw portion of the load measuring unit to the leaf spring holding bracket is screwed into the screw portion of the load measuring unit screwed into the screw hole,
The end of the leaf spring holding pin is supported only by the load supporting portion of the load measuring portion. According to the sixth aspect, the screw portion of the load measuring section is screwed into a screw hole formed in the leaf spring holding bracket, the position is adjusted, and the load measuring section is fixed to the leaf spring holding bracket with a nut, so that the load measurement is performed. The load supporting portion of the section is pressed against the tip of a leaf spring holding pin cantilevered by a leaf spring holding bracket, and the load supporting portion supports the tip of the leaf spring holding pin. Accordingly, unnecessary force is not applied to the load measuring unit at the time of assembly, calibration of the load measuring unit is not required, and the load measuring unit can be easily removed and replaced at the time of maintenance.

A seventh aspect of the present invention is characterized in that the root diameter of the screw portion is larger than the outer diameter of the conversion element and the outer diameter of the load supporting portion. According to the present invention, the conversion element and the load supporting portion project radially outward from the screw portion due to the root diameter of the screw portion set to be larger than the outer diameter of the conversion element and the outer diameter of the load supporting portion. Because there is no, it is easily housed in the screw hole formed in the leaf spring holding bracket at the time of assembly or replacement, and the assembly work and replacement work can be easily performed. The leaf spring holding bracket protects against external force, dust, and the like, so that highly accurate measurement can be stably performed over a long period of time.

According to an eighth aspect of the present invention, the diameter of the leaf spring retaining pin hole is 0.1 to 0.2 mm larger than the outer diameter of the leaf spring retaining pin. According to the present invention, the tip of the leaf spring holding pin is easily held by the leaf spring holding pin hole diameter set to be 0.1 to 0.2 mm larger than the outer diameter of the leaf spring holding pin. The load support section supports the tip of the leaf spring holding pin in a cantilevered state with the load support section, so that unnecessary force is not applied to the load measuring section during assembly and maintenance. No calibration of the measuring part is required.

A ninth aspect of the present invention is characterized in that a wiring path is formed in the screw portion of the load measuring section. According to the ninth aspect, by passing the signal line of the load measuring unit through the wiring passage formed in the screw portion of the load measuring unit, the signal line is not obstructed and is securely protected. No damage.

A tenth aspect of the present invention is characterized in that the load supporting portion and the leaf spring holding pin are configured to be in close contact with each other. According to the tenth aspect, the load is reliably transmitted from the leaf spring holding pin side to the load supporting portion by closely contacting the load supporting portion and the leaf spring holding pin, and the distortion of the main body portion is smoothly reduced. Is converted.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing a load measuring device according to an embodiment of the present invention, and FIG. 2 is a sectional view of FIG. Reference numeral 1 in the figure indicates that the diameter is, for example, 20 m.
It is a main body of the load measuring unit A made of a columnar steel material having a diameter of m. The main body 1 is distorted by a load applied from a direction indicated by an arrow P in FIG. A load support portion 2 is integrally formed at a lower portion of the main body portion 1, and a screw portion 3 and a hexagonal column-shaped head portion 4 are sequentially formed integrally at an upper portion of the main body portion 1.

On the other hand, reference numeral 10 denotes a leaf spring holding bracket attached to the vehicle body. The leaf spring holding bracket 10 is provided with a base end of a leaf spring holding pin 11, and a distal end of the leaf spring holding pin 11 is provided with a leaf spring holding pin formed on the leaf spring holding bracket 10. Is loosely fitted in the pin hole 12 for use. The diameter of the leaf spring holding pin hole 12 is set to be larger than the outer diameter of the leaf spring holding pin 11 by 0.1 to 0.2 mm (0.15 mm in the present embodiment).

A screw hole 13 for screwing the screw portion 3 is formed vertically from the upper surface of the leaf spring holding bracket 10 toward the leaf spring holding pin hole 12. A nut 14 for fixing the screw portion 3 to the leaf spring holding bracket 10 is screwed into the screwed screw portion 3.

Further, a leaf spring (leaf spring) 15 is connected to an intermediate portion of the leaf spring holding pin 11. A contact recess 16 having a flat surface that is in close contact with the lower surface of the load support portion 2 is formed at the tip of the leaf spring holding pin 11 at a position that contacts the flat lower surface of the load support portion 2. ing. This allows
The load P from the leaf spring holding pin 11 is smoothly and reliably transmitted to the load support 2 (main body 1).

Reference numeral 6 denotes a cylindrical magnetostrictive material (magnetic material) formed on the outer peripheral surface of the main body 1, for example, Fe: Ni: M
This magnetostrictive material 6 is formed integrally by being sprayed on the outer periphery of the main body 1. The magnetostrictive material 6 is for detecting distortion of the main body 1, and its magnetic characteristics (inductance and loss resistance) change according to the distortion of the main body 1.

The reason why the magnetostrictive material 6 is thermally sprayed onto the main body 1 without using an adhesive is that when measuring the strain of the main body 1 with the magnetostrictive material 6, the effect of the adhesive having a coefficient of thermal expansion one order of magnitude larger than that of the adhesive is used. This is because the measurement error based on the change in the magnetic characteristics of the magnetostrictive material 6 caused only by the temperature change is reduced as much as possible. The difference in the coefficient of linear expansion between the main body 1 and the magnetostrictive material 6 is set to 1 × 10 ⁻⁶ K ⁻¹ or less.

Reference numeral 7 denotes a coil formed by winding a magnet wire around the main body 1 through an insulating tape, for example, 200 times. The change in the magnetic characteristics of the magnetostrictive material 6 due to the distortion of the main body 1 is determined by its own impedance (inductance). And loss resistance). That is, it is for converting a magnetic change into an electric change.

Reference numeral 8 denotes a temperature compensation circuit arranged near the coil 7. As described above, the coefficient of thermal expansion of the main body 1 is different from the coefficient of thermal expansion of the magnetostrictive material 6.
However, the change in the magnetic characteristics due to the temperature change does not become completely zero, and the temperature drift still occurs. The temperature compensating circuit 8 is for extremely reducing the temperature drift.
This temperature compensation circuit 8 is connected to the coil 7 in series.

The root diameter of the thread portion 3 of the load measuring section A is set larger than the outer diameter of the coil 7 and the outer diameter of the load supporting section 2. 1 and 2 is a wiring hole formed by penetrating the screw portion 3 and the head 4 along the axis thereof, and the lower end of the screw portion 3 is provided with the wiring hole 9. A through hole 5 for wiring is formed in a state perpendicular to (in a direction perpendicular to the paper surface of FIG. 1). The through hole 5 is opened downward at the outer edge of the lower end of the screw portion 3, and a wiring path through which the signal line of the load measuring unit A can be inserted is formed by the wiring hole 9 and the through hole 5. Have been.

FIG. 3 is a circuit diagram showing an example of an electric circuit portion of the load measuring device of the present embodiment. Members corresponding to those shown in FIGS. 1 and 2 are denoted by the same reference numerals. I have. In FIG. 3, reference numeral 20 denotes an electrical equivalent circuit of the magnetostrictive material 6, the coil 7, and the temperature compensation circuit 8 in FIGS. That is, the magnetostrictive material 6 and the coil 7 are represented as variable impedances 22 in FIG. 3, and the temperature compensating circuit 8 is an NTC thermistor (Negative Temperature Coeffic
and a resistor 26 connected in parallel to the NTC thermistor with a small resistance change due to temperature change.
And an absolute value adjusting resistor 28 connected in series to a parallel resistor including an NTC thermistor 24 and a resistor 26.

The NTC thermistor 24 is a thermistor having a negative characteristic that its resistance value decreases with an increase in temperature. The change characteristic of the NTC thermistor 24 is that the resistance value does not decrease in direct proportion to the temperature increase, but is non-linear with the temperature increase It has the characteristic that the resistance value is reduced. This NTC thermistor 24
Is for compensating for a change in the impedance 22 due to a temperature change. Since the impedance 22 has a characteristic that its value increases as the temperature rises, NT has a negative characteristic to compensate for the temperature change of the impedance 22.
C thermist 24 is used.

The resistor 26 connected in parallel with the NTC thermistor 24 is for compensating the non-linear characteristic of the NTC thermistor 24 to become a linear characteristic. That is, N
When a parallel circuit including the TC thermistor 24 and the resistor 26 is viewed as one thermistor, the characteristics of the thermistor have a linear characteristic. When only the DC resistance of the impedance changes due to a temperature change, for example, FIGS.
When the temperature coefficient of the resistance component of the coil 7 in the middle is 0.4% / ° C., it is best to set the temperature coefficient of the parallel circuit of the NTC thermistor 24 and the resistor 26 to −0.4% / ° C. It is. The absolute value adjusting resistor 28 adjusts the resistance value of the entire temperature compensating circuit 8.

In FIG. 3, the signal processing circuit 40 includes an AC voltage source 42, a resistor 44, a rectifier circuit 46, and a zero point offset adjusting circuit 48. The AC voltage source 42 outputs a sine wave AC voltage.
Ob is connected to the impedance 22, and the other end is connected to the temperature compensation circuit 8 via the resistor 44 and the cable 40a. As described above, the AC voltage source 42, the cable 40
b, the equivalent circuit 20, and the resistor 44 form one closed circuit.

The resistor 44 converts a current flowing through the closed circuit into a voltage, and both ends thereof are connected to a rectifier circuit 46. The rectifier circuit 46 rectifies and smoothes the AC voltage converted by the resistor 44 and converts it into a DC voltage. The rectifier circuit 46 is connected to a zero-point offset adjusting circuit 48. The zero point offset adjusting circuit 48 adds an offset voltage to the DC voltage output from the rectifier circuit 46 or subtracts the offset voltage and outputs the result to the terminal 48a. Although not shown, the terminal 48a
Is connected to a signal processing unit that calculates the distortion of the main unit 1 based on the voltage value of the terminal 48a and measures the loaded weight. For example, when the voltage value output from the terminal 48a is 0 [V], the signal processing unit performs the calculation that the distortion of the main unit 1 is zero. Therefore, the zero point offset adjustment circuit 48 is required.

In the above configuration, when an AC voltage is output from the AC voltage source 42, an AC current flows in a closed circuit. The current flowing through the closed circuit is converted to an AC voltage by the resistor 44,
Rectification and smoothing are performed in the rectifier circuit 46 to be converted into a DC voltage, and an offset voltage is added or the offset voltage is subtracted in the zero-point offset adjusting circuit 48 to respond to the distortion of the main body 1 in FIGS. The voltage value appears at terminal 48a.

In the load measuring device configured as described above, when assembling the load measuring portion A to the bracket 10 for holding the leaf spring, the screw portion 3 is screwed into the screw hole 13 and the load supporting portion 2 is attached. After adjusting the position so as to contact the leaf spring holding pin 11, the nut 14 is screwed into the upper part of the screw portion 3 and fixed to the leaf spring holding bracket 10. Thereby, unnecessary force is not applied to the load measuring unit A at the time of assembly, and it is not necessary to calibrate the load measuring unit A. When replacing the load measuring section A during maintenance, the nut 14 is removed from the upper part of the screw section 3 and the screw section 3 is removed upward from the screw hole 13. What is necessary is just to mount in the screw hole 13.

At the time of assembling or exchanging the load measuring portion A, the root diameter of the screw portion 3 is set to be larger than the outer diameter of the coil 7 and the outer diameter of the load supporting portion 2. The coil 7 and the load supporting portion 2 do not hinder the screw portion 3 from being screwed into the screw hole 13. Also,
At the time of load measurement, the coil 7, the load support 2 and the temperature compensation circuit 8
With 0, it is possible to perform stable load measurement over a long period of time while being protected from external force or dust.

Further, a leaf spring retaining pin hole 1 is provided.
2 is 0.1 to 0.2 mm (0.15 mm in the present embodiment) from the outer diameter of the leaf spring holding pin 11.
Because of the large setting, the tip of the leaf spring holding pin 11 can be easily inserted into the leaf spring holding pin hole 12.
And the load supporting portion 2 can support the tip of the leaf spring holding pin 11 in a cantilevered state.

Further, the load measuring section A is formed by using the through holes 5 and the wiring holes 9 formed in the screw section 3 and the head 4.
The signal line does not interfere with the signal line, and the signal line is protected from vibration or external force by the screw portion 3 and the head portion 4 and is not damaged.

Although the load sensor according to one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and can be freely changed within the scope of the present invention. For example, in the above embodiment, the main body 1 has a cylindrical shape, but may have a cylindrical shape, a prism shape, or a rectangular tube shape. The shape may be easy.

In the above embodiment, the main body 1, the load support 2, the screw 3, and the head 4 are integrally formed. However, the present invention is not limited to this.
It goes without saying that the configuration may be divided into a plurality of parts. For example, as shown in FIGS. 4, 5 and 6, a configuration in which the main body 61, the load supporting portion 62, and the screw portion 63 having the head 64 are separated into three parts may be used.

In this case, the wiring hole 65 penetrating through the center of the screw portion 63 is formed at the upper end of the main body 61 in a direction perpendicular to the axis thereof (in the direction perpendicular to the paper of FIG. 4). The wiring groove 66 communicates with the groove 66.
The vertical groove 67 formed on the outer periphery of the upper end of the main body 61
The wiring hole 65, the wiring groove 66, and the vertical groove 67 constitute a wiring path.

An annular mounting recess 68 is formed on the outer periphery of the main body 61. The mounting recess 68 has the magnetostrictive material 6, coil 7 and temperature compensation circuit shown in FIGS. 8 are attached, and the same reference numerals are attached and the description is omitted (in FIGS. 4 to 6,
The temperature compensation circuit 8 is not shown).

Further, the lower surface of the load supporting portion 62 is formed in a concave curved shape so as to be in close contact with the outer peripheral curved surface of the leaf spring holding pin 11, and thus the lower surface of the load supporting portion 62 is formed. By doing so, it is not necessary to form the contact recess 16 in the leaf spring holding pin 11.

[0039]

According to a first aspect of the present invention, a leaf spring fixing pin is provided in a cantilever shape, and a load measurement supporting the leaf spring fixing pin is opposed to the tip of the leaf spring fixing pin. The load is directly measured by the load measuring unit by supporting the tip (free end) of the cantilevered leaf spring holding pin by the load measuring unit. be able to. Therefore, load measurement can be performed with high accuracy, calibration is not required at the time of assembling to a vehicle, and it is possible to easily assemble and easily replace at the time of maintenance.

According to a second aspect of the present invention, the load measuring section comprises: a main body which is distorted by a load; a screw provided on an upper part of the main body; a load support provided on a lower part of the main body; A magnetic material that is sprayed on the outer peripheral surface of the main body and has a magnetic property that changes in accordance with the distortion of the main body, and a magnetic material that is disposed on the outer periphery of the magnetic material and that changes the magnetic property of the magnetic material with an electrical impedance. A conversion element for converting the change into a change, a temperature compensation circuit connected to the conversion element, for compensating the change in the impedance based on the temperature change, and detecting the change in the impedance based on the distortion of the main body; And measuring means for measuring the strain, so that when the main body is distorted by the load received by the load supporting portion, the magnetic material is The magnetic properties of Is converted into a change in electrical impedance by a conversion element, and a change in the impedance due to a change in temperature is compensated for by a temperature compensation circuit, and the impedance is converted into distortion of the main body by measurement means. By measuring the load applied to the main body, the loaded weight of the truck and the like can be measured smoothly and accurately.

A third aspect of the present invention is characterized in that the difference in linear expansion coefficient between the main body and the magnetic material is 1 × 10 ⁻⁶ K ⁻¹ or less. By setting the difference of the coefficient of linear expansion of the magnetic material to 1 × 10 ⁻⁶ K ⁻¹ or less, the magnetic properties (inductance and loss resistance) of the magnetic material due to temperature change
Can be suppressed as much as possible, and a measurement error (temperature drift) caused by a temperature change can be reduced as much as possible.

According to a fourth aspect of the present invention, the conversion element is a coil wound around the outer periphery of the magnetic material. By converting a change in the magnetic properties of the material into a change in the electrical impedance, the variation in the strain between the magnetic material and the main body can be averaged, and the strain can be detected with high accuracy.

According to a fifth aspect of the present invention, the main body has a cylindrical shape.
Since it is characterized by being cylindrical, prismatic, or prismatic, the manufacture of the main body is easy, and the magnetic material is easily sprayed on the outer peripheral surface of the main body.

According to a sixth aspect of the present invention, a leaf spring holding bracket is provided with a base end of a leaf spring holding pin, and a distal end of the leaf spring holding pin is formed on the leaf spring holding bracket. A screw hole that is loosely fitted in the leaf spring holding pin hole and that is screwed into the screw portion of the load measuring unit from the upper surface of the leaf spring holding bracket toward the leaf spring holding pin hole is formed in a vertical direction. A nut for fixing the screw portion of the load measuring unit to the leaf spring holding bracket is screwed into the screw portion of the load measuring unit screwed into the screw hole,
Since the tip of the leaf spring holding pin is configured to be supported only by the load support part of the load measurement part, the load measurement part is provided in the screw hole formed in the leaf spring holding bracket. Screw, adjust the position, and fix it to the leaf spring holding bracket with a nut, so that the load support section of the load measuring section can be connected to the leaf spring holding pin cantilevered by the leaf spring holding bracket. By pressing against the distal end, the load supporting portion can support the distal end of the leaf spring holding pin. Accordingly, unnecessary force is not applied to the load measuring unit at the time of assembly, and it is not necessary to calibrate the load measuring unit, and the load measuring unit can be easily removed and replaced at the time of maintenance.

The seventh aspect of the present invention is characterized in that the root diameter of the screw portion is larger than the outer diameter of the conversion element and the outer diameter of the load supporting portion. With the root diameter of the thread set to be larger than the outer diameter of the part, the conversion element and the load support part do not protrude outward in the radial direction from the thread, making it easy to hold the leaf spring during assembly or replacement. It can be housed in the screw hole formed in the hole, making it easy to perform assembling work and replacement work.At the time of load measurement, the conversion element and load support part can be Power, dust, and the like, and highly accurate measurement can be stably performed over a long period of time.

The eighth aspect of the present invention is characterized in that the diameter of the leaf spring retaining pin hole is 0.1 to 0.2 mm larger than the outer diameter of the leaf spring retaining pin. The tip of the pin is easily loosely fitted into the leaf spring holding pin hole, and the cantilevered leaf spring holding pin is supported by the load support section. Necessary force is not applied and there is no need to calibrate the load measuring unit.

According to a ninth aspect of the present invention, since the wiring passage is formed in the screw portion of the load measuring portion, a load is applied to the wiring passage formed in the screw portion of the load measuring portion. By passing the signal line of the measuring section, the signal line does not get in the way and is firmly protected and does not get damaged.

According to a tenth aspect of the present invention, since the load supporting portion and the leaf spring holding pin are configured to be in close contact with each other, the load supporting portion and the leaf spring holding pin are in close contact with each other. Thus, the load can be reliably transmitted from the leaf spring holding pin side to the load support portion, and the distortion can be smoothly converted as the distortion of the main body portion. Therefore, the load (vehicle loading weight)
Can be accurately measured.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a load measuring device according to an embodiment of the present invention.

FIG. 2 is a sectional view of FIG. 1 as viewed from a side.

FIG. 3 is a circuit diagram showing an electrical configuration of the load measuring device according to the embodiment.

FIG. 4 is an exploded front view showing a load measuring unit according to another embodiment of the present invention.

FIG. 5 is a side view of FIG. 4;

FIG. 6 is a plan view of FIG. 4;

[Explanation of symbols]

 A Load measuring part P Load 1, 61 Body part 2, 62 Load supporting part 3, 63 Screw part 5 Through hole (wiring path) 6 Magnetostrictive material (magnetic material) 7 Coil (conversion element) 8 Temperature compensation circuit 9 Wiring hole (Wiring passage) 10 Leaf spring holding bracket 11 Leaf spring holding pin 12 Leaf spring holding pin hole 13 Screw hole 14 Nut 15 Leaf spring (leaf spring) 40 Signal processing circuit (measuring means) 65 Wiring hole (for wiring) Passage) 66 Wiring groove (wiring path) 67 Vertical groove (wiring path)

Claims (10)

[Claims] 1. A load measuring device provided on a leaf spring holding pin for holding a leaf spring and measuring a vehicle loading weight, wherein the leaf spring fixing pin is provided in a cantilever shape, and the leaf spring is fixed. A load measuring unit for supporting the leaf spring fixing pin, which is opposed to a tip end of the load pin. 2. A load measuring unit comprising: a main body distorted by a load; a screw provided on an upper part of the main body; a load supporter provided on a lower part of the main body; and an outer peripheral surface of the main body. A magnetic material that is thermally sprayed on the magnetic material and changes its magnetic characteristics in accordance with the distortion of the main body; and a conversion element that is disposed around the magnetic material and converts a change in the magnetic characteristics of the magnetic material into a change in electrical impedance. A temperature compensating circuit connected to the conversion element for compensating the change in the impedance based on a temperature change; and a measuring means for detecting the change in the impedance based on the distortion of the main body and measuring the distortion of the main body. The load measuring device according to claim 1, comprising: 3. The difference in linear expansion coefficient between the main body and the magnetic material is 1
The load measuring device according to claim 2, wherein the load measuring device is equal to or less than × 10 ^-6 K ^-1 . 4. The load measuring device according to claim 2, wherein the conversion element is a coil wound around the outer periphery of the magnetic material. 5. The load measuring device according to claim 2, wherein the main body has a cylindrical shape, a cylindrical shape, a prismatic shape, or a rectangular cylindrical shape. 6. A bracket for holding a leaf spring,
A base end of the leaf spring holding pin is provided, and a distal end of the leaf spring holding pin is loosely fitted into a leaf spring holding pin hole formed in the leaf spring holding bracket, and the leaf spring holding bracket is provided. A screw hole for screwing the screw portion of the load measuring portion is formed in the vertical direction from the upper surface of the leaf spring holding pin hole, and the screw portion of the load measuring portion screwed into the screw hole is provided with the screw hole. The nut for fixing the screw part of the load measuring part to the leaf spring holding bracket is screwed in, and the tip of the leaf spring holding pin is configured to be supported only by the load supporting part of the load measuring part. The load measuring device according to claim 2, 3, 4, or 5, wherein: 7. The thread diameter of the thread portion is larger than the outer diameter of the conversion element and the outer diameter of the load supporting portion.
The load measuring device as described. 8. The hole diameter of the leaf spring holding pin is 0.1 to 0.2 mm from the outer diameter of the leaf spring holding pin.
8. The load measuring device according to claim 6, wherein the load measuring device is large. 9. A wiring path is formed in a screw portion of the load measuring section.
Or the load measuring device according to 8. 10. The load measuring device according to claim 6, wherein the load supporting portion and the leaf spring holding pin are configured to be in close contact with each other.