JP3468728B2 - Seat weight measuring device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for measuring seat weight including the weight of an occupant sitting on a vehicle seat. In particular, the present invention relates to a low-priced seat weight measuring device that is excellent in vehicle environment resistance.

[0002]

2. Description of the Related Art Vehicles are equipped with seat belts and airbags as equipment for ensuring the safety of passengers. Recently, in order to further improve the performance of seat belts and airbags, there is a trend to control the operation of the safety equipment according to the weight (weight) of the occupant. For example, the deployment gas amount and deployment speed of the airbag are adjusted or the pretension of the seat belt is adjusted according to the weight of the occupant. To do so, it is necessary to know the weight of the occupant sitting on the seat by some means. As an example of such means, a proposal has been made that load sensors (load cells) are arranged at four corners of a seat rail and the vertical load applied to the load cells is totaled to measure a seat weight including an occupant's weight. (Japanese Patent Application No. 9-156666 and Japanese Patent Application No. 10-121 by the same applicant)
627).

As a load sensor for the seat weight measuring apparatus as described above, a small one with a maximum measurement load of about 50 kg is desired. Such load sensors include those in which a strain gauge is attached (or formed) to a sensor plate that flexes under load, piezoelectric type, and displacement of an elastic member that flexes under load is detected by a capacitance sensor. There are things.
A metal thin film gauge is generally used as the strain gauge. The method of manufacturing this metal thin film gauge is as follows. That is, the metal thin film attached to the resin film is etched to form a gauge portion including a wiring portion and a thin wire. After that, it is sandwiched with a resin film and attached to spring steel. Then, by adjusting the temperature coefficient (coefficient indicating the relationship between temperature and linear expansion) of the spring steel and the metal thin film, it is possible to configure a load sensor having excellent strain characteristics and temperature coefficient.

[0004]

However, the strain gauge as described above has a high manufacturing cost because the manufacturing process is complicated. Further, the work of adhering the strain gauge accurately and uniformly requires a lot of work, and the assembling cost is high. Furthermore, since the output voltage of the strain gauge is small, a noise shield and a high-sensitivity amplifier are also required, which is a factor of high cost. By the way, the gauge portion formed of a metal wiring portion and a thin wire is sandwiched between resin films to improve heat resistance (generally −35 ° C. to + 80 ° C.) and corrosion resistance. However, if a sufficient additional seal is not provided in a high temperature and high humidity environment such as in a vehicle, insulation failure may occur in a severe operating environment.

The present invention has been made in view of the above problems, and is an apparatus for measuring the seat weight including the weight of an occupant sitting on a vehicle seat, which reduces processing costs and assembly costs. An object of the present invention is to provide a seat weight measuring device that can be used. Furthermore, it aims at providing the seat weight measuring device which can improve heat resistance and corrosion resistance.

[0006]

In order to solve the above problems, a seat weight measuring apparatus of the present invention is an apparatus for measuring a seat weight including a weight of an occupant sitting on a vehicle seat. And a load sensor inserted into the seat or between the seat and the vehicle body for receiving at least a part of the seat weight and converting the same into an electric signal, wherein the load sensor is at least a part of the seat weight. And a strain gauge arranged on the surface of the sensor member.
The strain gauge includes a lower insulating layer, a wiring layer, a resistance layer, and an upper insulating layer that are sequentially and selectively stacked on the surface of the sensor member, and the lower insulating layer contains a vitreous material. A displacement gauge that limits the strain of the strain gauge to 1500 με or less when a load is applied to the sensor.
A control mechanism is provided, and the displacement regulation mechanism is
Between the seat and the seat fixing part of the vehicle body, the relative change of both
That it is designed to regulate the position within a certain range.
Characterize.

Since the strain gauge has a laminated structure,
For example, it can be formed by printing or the like, and mass productivity can be improved. Since the strain gauge is directly formed on the sensor member, the assembly is easy. Further, since the upper insulating layer can be formed as the protective layer, it is not necessary to provide an additional seal. The purpose of the seat weight measuring device in this specification is basically to measure the weight of an occupant on the seat. Therefore, a device for canceling the weight of the seat itself and measuring only the weight of the occupant is also included in the seat weight measuring device herein.

In the present invention, the sensor member has an elongation of 0.
It is preferably made of a material that withstands repeated elastic deformation of 1% or more. Since the permanent strain does not accumulate at least by expansion and contraction of 0.1% or more, it can be used as a sheet sensor. In the present invention, it is preferable that each layer is formed by applying an insulating material paste, a wiring material paste, or a resistance material paste in a certain pattern and then solidifying it.
In particular, the insulating layer preferably contains a glassy material. Since it is a paste, it can be formed by printing or the like, and mass productivity can be improved. Further, since it contains a glassy material, heat resistance and corrosion resistance can be improved.

In the present invention, it is preferable that the sensor member is made of stainless steel and each of the above layers is solidified by firing. By using heat-resistant stainless steel, the sensor member can be fired together when each layer is fired at a high temperature. In the present invention, it is preferable that the lead wire and the connection terminal with the additional component are also laminated. It is possible to enhance productivity by stacking lead terminals and connection terminals with additional components. Here, the additional parts are
For example, the following can be mentioned. A resistance element or semiconductor element for correcting the sensitivity characteristics of the strain sensor,
A temperature sensitive resistance element for correcting the temperature characteristics of the strain sensor, a semiconductor temperature sensor, a capacitor for electrically protecting the strain sensor, a semiconductor element, and an amplifier circuit for lowering the output impedance of the strain sensor.

In the present invention, the strain of the strain gauge is 1500 με when a load is applied to the load sensor.
It is as follows . Here, the strain applied to the sensor member is 15
It is preferable to provide a displacement regulation mechanism for limiting the displacement to 00 με or less. If the strain is in this range, the strain gauge and the sensor member can be prevented from being damaged. Strain gauge strain is 1 under maximum load (eg 100 kgf)
It is preferably 000 to 1500 με. If the output of the strain gauge is sufficiently high, accurate measurement can be performed.

In the present invention, it is preferable that the surface strain of the sensor member near the strain gauge is made uniform by the shape deflection of the sensor member. Since the surface strain of the sensor member is made uniform, it is possible to improve the measurement accuracy and prevent the sensitivity from changing. In the present invention,
It is preferable that the strain gauge has a bridge circuit, and the resistance of the piece is 500Ω to 5000Ω. Within this range, heat generation due to an increase in current can be prevented, and weight detection can be performed stably.

A description will be given below with reference to the drawings. Figure 1
FIG. 2 is a sectional side view showing a configuration example of a sensor (strain gauge) of the seat weight measuring device according to one embodiment of the present invention. 2A is a plan view of a sensor plate (sensor member) having the sensor of FIG. 1, and FIG. 2B is a circuit diagram of the sensor. Note that FIG. 1 shows a cross-sectional side view taken along line XX ′ of FIG. The sensor 30 includes an insulating layer (lower insulating layer) 3 for electrical insulation on a sensor plate (spring material) 31 which is a base material.
2 is formed. A wiring layer 33 is formed on the insulating layer 32.
Are selectively formed. Further, a resistance layer 34 is selectively formed on the wiring layer 33 to form a strain gauge. Then, an insulating layer (upper insulating layer) 35 as a protective film for these is formed. in this way,
Since an electric circuit such as a resistor is directly laminated on the spring material 31, the processing cost and the assembly cost can be reduced.
Furthermore, heat resistance and corrosion resistance can be improved.

The sensor plate 41 is a rectangular plate with rounded corners as a whole. In this example, the material is stainless steel, which has a strain rate of 0.1% or more and withstands repeated elastic deformation, and has a total length of 80 mm, a width of 40 mm, and a thickness of 3 mm. A central shaft hole 41a having a diameter of 10 mm is formed in the central portion of the sensor plate 41. Bolt holes 41b having a diameter of 8 mm are formed at both ends of the sensor plate 41. A sensor 30 is formed from the peripheral edge of the central shaft hole 41a to between the central shaft hole 41a and both bolt holes 41b. A region 41c between the central shaft hole 41a and both bolt holes 41b in the formation region of the load sensor 30.
Has a conical neck on each side. Due to this constriction, the deformed portion of the sensor plate 41 is fixed in position, so that the position change of the surface strain of the sensor 30 is fixed and the sensitivity becomes stable.

The sensor 30 is arranged substantially symmetrically with respect to the center of the central shaft hole 41a. That is, the sensor 30
Of the four strain resistors 34a, 34b, 34c, 34
d is 2 on the tensile strain side near the bolt hole 41b (closer to the end).
The strain resistors 34a and 34b are arranged separately from the two strain resistors 34c and 34d on the compression strain side near the central shaft hole 41a (close to the center). Then, the four strain resistors 34a,
The wirings 33a, 33b, 33c, and 3 are arranged so that the wirings 34b, 34c, and 34d are bridge circuits as shown in FIG.
It is connected by 3d. 1, 2 in the square in the figure,
Items with numbers 3 and 4 indicate terminals.

The strain resistors 34a, 34c and the strain resistor 3
A sensitivity adjustment resistor 34e is arranged between 4b and 34d. The sensitivity adjusting resistor 34e is a central axis in the vicinity of the terminals 1 and 3 which are protrusions deviated from the lines of force in consideration of the reliability of solder and mechanical stress on components, where the sensor plate 41 has less distortion. It is formed in a bridge shape near the hole 41a and soldered. An amplifier for amplifying a signal may be connected instead of the sensitivity adjusting resistor 34e, or a temperature characteristic adjusting element may be connected. By forming the connection terminal of the component that corrects the characteristics of the strain sensor on the sensor plate integrally with the terminal for the strain sensor, the processing cost can be reduced, and
Characteristics such as temperature drift can be improved.

Here, in the in-vehicle system, it is important to reduce the impedance of the signal line in addition to the magnitude of the electric output. In addition to radio noise, it is important for the seat legs to take measures against electric leaks such as humidity, dust containing salt, and water drops.
Stable weight detection is difficult unless the resistance value of is reduced. Although the strain resistance material itself has a sheet resistance of 10 kΩ or more and high sensitivity, the resistance value becomes high. Further, since the seat weight starts to be measured at the same time as the ignition of the vehicle is started, the starting stability is also important. If the resistance value becomes too small, the current flowing through the resistance increases, causing a slight drift due to heat generation. Therefore, the resistance value of the bridge (or half bridge) is preferably in the range of 500Ω to 5000Ω.
It should be noted that instead of detecting the strain of the sensor plate 41 by the strain resistors 34a, 34b, 34c, 34d, even if the deflection of the sensor plate 41 is detected by a capacitance sensor or a Hall element and the deflection is converted into a load. Good.

FIG. 3 is a side view schematically showing the overall construction of the seat weight measuring apparatus according to one embodiment of the present invention. Hereinafter, in this specification, when simply referred to as front / rear and left / right, it means front / rear and left / right as viewed from the occupant 1. In the figure, a seat 3, an occupant 1 above it, and a seat weight measuring device 5 below the seat are shown.
Etc. are shown. The seat 3 includes a seat cushion 3a on which the occupant 1 sits and a seat back 3b which is a backrest. Seat adjusters 10 are provided on the bottom surface of the seat cushion 3a at four positions in front, back, left and right. Although only the two front and rear adjusters 10 on the left side are shown in the drawing, the seat adjuster 10 on the right side is hidden behind them. Such a relationship in the drawings is the same for each unit of the present apparatus described below. Seat adjuster 10
Is a part of the frame in the seat 3 that is projected, and can be slid back and forth on the seat rail 11 by the adjustment of the occupant 1.

The seat rail 11 has a groove cross section (not shown).
And a member that extends in the front-rear direction of the vehicle. The lower end of the seat adjuster 10 slides in the groove. Two left and right seat rails 11 are provided below the seat cushion 3a. In a conventional seat that does not have a seat weight measuring device, the seat rail 11 is firmly fixed to the seat bracket of the chassis of the vehicle body with bolts. An anchor fixing portion 12 for fixing the buckle 4 of the seat belt 2 is provided at one position behind the seat rail 11.
The tension of the seat belt 2 is applied to the anchor fixing portion 12. The breaking load of the anchor fixing portion 12 is 2300 kgf assuming a vehicle collision.

Below the seat rail 11, two sets of front and rear seat weight measuring devices 5 are provided. Two sets of front and rear seat weight measuring devices 5 are provided under the right seat rail (not shown). After all, below the seat 3, the seat weight measuring devices 5 are provided at four front, rear, left and right positions. Has been. Each seat weight measuring device 5 includes a seat holding mechanism 1
7 and a displacement regulation mechanism 25, and is arranged between the seat rail 11 and the seat fixing portion 19. In this example, the seat holding mechanism 17 includes a load sensor 13 and a bending member 15 that are connected in series. Load sensor 13
Detects the load applied to the seat holding mechanism 17.
The flexure member 15 is a member for increasing the displacement (movement) of the seat rail 11 when the weight of the occupant is applied to the seat 3.

In this example, the displacement regulation mechanism 25 comprises a regulation bar 21 connected to the lower surface of the seat rail 11 and a regulation block 23 formed on the seat fixing portion 19.
The tip portion 21a of the regulation bar 21 is enlarged in a flange shape. The regulation block 23 has a recess 23a inside. At the upper end of the recess 23a, a collar 23b protruding inward is formed.
Are formed. The regulation bar tip 21a is accommodated in the recess 23a of the regulation block with gaps in the vertical, front-rear, and left-right directions.

When an abnormal load is applied to the seat rail 11 and the load sensor 13 and the bending member 15 are deformed to a certain extent or more, the regulation bar tip portion 21a of the displacement regulation mechanism 25.
Comes into contact with the inner wall of the recess 23a of the regulation block. For example, if the seat belt 2 restrains the occupant 1 from moving forward in a vehicle collision, the seat belt 2 is tensioned by the inertial force of the occupant 1. At this time, the restriction bar 21 tries to move up, but its movement is stopped by the restriction bar tip portion 21a hitting the lower surface of the restriction block collar 23b. In this way, the displacement regulating mechanism 25 for regulating the relative displacement between the seat and the seat fixing portion within a certain range is provided between the seat and the seat fixing portion, and the load sensor 13 receives a force more than the specified value (for example, a force exceeding the measurement range). In this case, the excess load is handled not by the load sensor 13 but by the displacement regulating mechanism (load limiting mechanism) 25. Therefore, the breaking load required for the load sensor 13 can be remarkably low, and the load sensor 13 can be downsized and reduced in cost. Further, it is possible to limit the strain of the fired film (each sensor layer) which is relatively fragile.

Next, the relationship between the displacement regulating mechanism 25 and the bending member 15 of the sheet holding mechanism 17 will be described. If there is no flexible member 15 (it is a rigid member), the deformation of the load sensor 13 in the entire measurement range is 0.
If it is on the order of 1 mm, the gap between the regulation bar tip 21a of the displacement regulation mechanism 25 and the regulation block recess 23a also needs to be about 0.1 mm. This is because, when the load exceeds the measurement range, the regulation bar tip portion 21a needs to hit the inner surface of the regulation block recess 23a so that the overload is applied to the displacement regulation mechanism 25.

That is, the displacement regulating mechanism 25 is also required to have an operating accuracy corresponding to a stroke of 0.1 mm of the load sensor 13 described above, and the dimensional accuracy and mounting accuracy of parts are on the order of 0.01 mm. This is not possible at all with the current dimensional accuracy around the seats of automobiles mainly for press-formed products. Eventually, due to the small bending stroke of the load sensor 13, the displacement regulating mechanism (load limiting mechanism) 25 and its peripheral members are required to have high dimensional accuracy. In the present embodiment, the bending stroke of the sheet holding mechanism 17 in the measurement range of the load sensor 13 or the load bearing range is amplified by the action of the bending member 15 of the sheet holding mechanism 17. Therefore, it is possible to relax the requirements for the dimensional accuracy and the mounting accuracy of the members that form the sheet holding mechanism 17 and the displacement regulation mechanism 25.

Next, specific examples of the sheet holding mechanism and the displacement regulating mechanism will be described. FIG. 4 is a diagram showing the structure of a seat weight measuring apparatus according to one embodiment of the present invention. (A) is an overall side sectional view, and (B) is a plan view of a sensor plate. The seat rail 11 is shown at the top of the drawing. Under the seat rail 11, the sensor frame upper plate 51
And the sensor frame 53 is attached by the bolt 52. The sensor frame upper plate 51 is a strong plate and has a hole 51a in the center thereof. Sensor frame 53
Is a dish-like shape with a concave inside. A flange portion 53a is formed on the outer periphery of the upper portion of the frame 53, and the sensor frame upper plate 5 is formed by the bolt 52 at the same portion as described above.
It is attached to 1. Bottom plate 5 of sensor frame 53
A hole 53c is opened in the center of 3b.

A sensor plate 57 is fixed to the lower surface of the sensor frame upper plate 51 with bolts 55. The sensor plate 57 in this example is made of stainless steel and has a thickness of 3 mm and a width of 2 mm.
It is a rectangular plate with a length of 0 mm and a length of 80 mm. As shown in FIG. 4B, the central axis through hole 5 is formed in the central portion of the sensor plate 57.
7c is opened, and bolt holes 57a are opened on both sides. On the upper surface of the sensor plate 57, the front and rear (see FIG.
A sensor having two strain resistors 57b is formed on each side of (B). These strain resistors 57b detect the strain of the sensor plate 57 and measure the load applied to the plate 57.

A central shaft 59 is fitted in a central hole 57c of the sensor plate 57, and both are fixed by a nut 59a. Bolts 55 are provided in the holes 57a on both sides of the sensor plate 57.
Is fitted from bottom to top. The sensor plate 57 is fixed to the sensor frame upper plate 51 by the bolts 55.

The central shaft 59 is a cylindrical shaft having a plurality of steps and flanges. The central axis 59 is
The upper nut 59a, the flange portion 59b, the sensor frame penetrating portion 59c, the small diameter portion 59d, the lower nut 59e, and the like are included. The upper nut 59a fixes the sensor plate 57 as described above. Further, the nut 59a is inserted into the central hole 51a of the sensor frame upper plate 51. Between the nut 59a and the hole 51a, in a standard state, a gap of 0.25 mm in the vertical direction and 0.5 mm in the circumferential direction is provided as an example. When the force applied to the seat rail 11 increases and the deformation of the sensor plate 57 and the like increases, the nut 5
9a contacts the inner surface of the hole 51a. At that time, the deformation of the sensor plate 57 does not proceed any further. That is, the center shaft upper nut 59a and the sensor frame upper plate central hole 51a form a displacement regulating mechanism.

The outer diameter of the flange portion 59b of the central shaft 59 is
It is larger than the central hole 53c of the sensor frame 53, and the lower surface of the same portion 59b faces the upper surface of the sensor frame bottom plate 53b with a gap of 0.25 mm in the standard state. When an upward force is applied to the seat rail 11 and the deformation of the sensor plate 57 progresses, the sensor frame 53 is lifted, and the central upper surface 53d of the frame bottom plate 53b comes into contact with the bottom surface of the central shaft flange portion 59b. By the way, a gap of 0.7 mm exists between the outer periphery of the sensor frame penetrating portion 59c of the central shaft 59 and the inner periphery of the sensor frame central hole 53c in the standard state. This part also constitutes the displacement regulation mechanism.

The small-diameter portion 59d of the central shaft 59 is one step thinner from the sensor frame penetrating portion 59c and extends downward. A nut 59e is screwed onto the tip of the small diameter portion 59d. A washer 61, a rubber washer 63, a sensor base 65, a rubber washer 63, and a washer 61 are fitted on the outer periphery of the small diameter portion 59d from the top to the bottom. The washer 61 is made of metal. The rubber washer 63 expands and contracts by about 0.5 mm when the load is changed by about 50 kgf in the vertical direction. The rubber washer 63 plays a role of absorbing a dimensional difference and distortion between the seat rail 11 and the seat fixing portion (seat bracket 67). The sensor base 65 is a metal plate and is the lowermost member of the seat weight measuring apparatus of this embodiment. The upper and lower two washers 61, the same two rubber washers 63, and the sensor base 65 include a step portion below the sensor frame penetrating portion 59c of the central shaft 59 and a lower nut 59e.
It is sandwiched between and. The end portion 65b of the sensor base 65
Are fixed to the seat bracket 67 with bolts (not shown). The seat bracket 67 is projectingly provided on the chassis.

The overall operation of the seat weight measuring apparatus of the embodiment shown in FIG. 4 will be described collectively. The weight of the seat and the occupant on the seat rail 11 is normally determined by the sensor plate 57.
Through the central shaft 59, the rubber washer 63, the sensor base 65, and the seat bracket 67. At this time, the sensor plate 57 causes a deflection substantially proportional to the load, which is detected by the strain resistance 57b, and the vertical load applied to the sensor plate 57 is measured. The weight of the occupant can be known by summing the measured loads of the front, rear, left and right load sensors and subtracting the weight of the seat, seat rail, etc. from the total value. 10 for load sensor
When a load of 0 kgf is applied, the strain of the strain resistance 57b is 15
It is set to 00 με or less, preferably 1000 με.

On the other hand, when the seat rail 11 is subjected to a measurement range of the load sensor (for example, 1500 με or less) or an abnormal force exceeding the load load limit, the central shaft nut 59a is attached to the inner surface of the sensor frame upper plate central hole 51a. The central shaft flange portion 59b and the sensor frame penetrating portion 59c come into contact with the sensor frame bottom plate 53b.
By such a function of the displacement regulating mechanism, the sensor plate 57 is prevented from being excessively deformed, and the seat rail 11 and the seat bracket 67 are firmly connected.

Here, generally, in an in-vehicle environment, it is necessary to obtain a large electric output in order to eliminate the influence of noise, and it is necessary to apply as much deformation strain as possible to the sensor plate. Therefore, just below the resistor for detecting the deformation of the sensor plate may be deformed with the maximum strain allowed by the base material or the laminated portion (sensor). However, if the strain is concentrated on a part of the sensor plate, the sensitivity will vary depending on the strain of the sensor plate, and further local concentration will occur due to impact or the like, resulting in damage beyond the allowable limit.
Therefore, in order to maximize the use of the allowable range of the sensor plate and the laminated portion, the deformation stress should be diffused and the surface strain amount of 70% or more of the maximum strain amount generated on the sensor plate around the resistance should be generated uniformly. The sensor plate may be formed on the.

FIG. 5A is a plan view of a sensor plate of another form of the seat weight measuring apparatus according to one embodiment of the present invention, and FIG. 5B is a circuit diagram of the sensor. Sensor plate 7
1 is a diamond plate. In this example, the material is stainless steel, and the overall length is 80 mm, the maximum width is 40 mm, and the thickness is 3 mm. The central portion of the sensor plate 71 has a central shaft hole 7 with a diameter of 10 mm.
1a is opened. Bolt holes 71b having a diameter of 8 mm are formed at both ends of the sensor plate 71. Sensor plate 71
By tapering the shape from the central part to both ends, the bending curvature of the sensor plate 71 is made constant so that surface strain is not localized. Strain resistors are laminated and formed in a region A where the surface strain of both taper portions is constant and a region B where no strain occurs in the central portion, and wiring is laminated so as to form a bridge circuit as shown in FIG. 5B. And use it as a sensor. Because of this taper, the deformed portion of the sensor plate 71 is fixed in position, so that the position change of the surface strain of the sensor is fixed and the sensitivity becomes stable.

Although each of the above-mentioned sensor plates is an example corresponding to a bending load, a sensor plate corresponding to a tensile load can be similarly applied. FIG. 6 is a plan view of a sensor plate of still another form of the seat weight measuring apparatus according to one embodiment of the present invention. The sensor plate 81 is a rectangular plate with rounded corners as a whole. In this example, the material is stainless steel, and the overall length is 80 mm, the width is 40 mm, and the thickness is 3 mm. Bolt holes 81 with a diameter of 8 mm are provided on both ends of the sensor plate 81.
b is open. Area 81 at the center of the sensor plate 81
A has a constriction which is scooped in a substantially rounded shape on both sides so that the surface strain is constant, thereby forming a sensor. Due to this constriction, the portion where the sensor plate 81 is deformed is fixed in position, so that the position change of the surface strain of the sensor is also fixed and the sensitivity becomes stable.

A method of manufacturing the above-described sensor 30 will be sequentially described below. (1) Material of spring material 31: SUS430 (2) Forming / forming method of insulating layer 32: screen printing / forming material: glass paste / forming thickness: 30 μm, firing 850 °

(3) Formation of wiring layer 33 ・ Forming method: Screen printing ・ Forming material: Ag / Pt paste ・ Formation thickness: 10 μm to 20 μm, firing 850 ° (4) Formation of resistance layer 34 ・ Forming method: Screen printing ・ Forming material: Ru-based resistor paste ・ Formation thickness: 20 μm, firing 850 °

(5) Method of forming / forming insulating layer 35: Screen printing / forming material: Glass paste (manufactured by Tanaka Kikinzoku Co., Ltd., trade name LS-402 (firing temperature 530 °), LS-453 (firing temperature 850 °)) According to the manufacturing method described above, a sheet material that does not require high-precision processing can be formed of a solid material whose resistivity greatly changes with strain. Mass production can be improved by eliminating the step of sticking to the material.

The present invention is not limited to the above-mentioned various embodiments, and various modifications can be added according to the basic idea shown in the claims.

[0039]

As is apparent from the above description, the present invention exhibits the following effects. Since the strain gauge has a laminated structure, it can be formed by, for example, printing, so that mass productivity is high and processing cost can be reduced. Since the strain gauge is directly formed on the sensor member, it is possible to reduce the assembly cost. Further, since the upper insulating layer can be formed as the protective layer, heat resistance and corrosion resistance can be improved. It is possible to enhance the mass productivity and reduce the cost when the lead wire and the connection terminal with the additional component are formed in layers to form the load sensor. Also,
Since the displacement regulating mechanism is provided, the strain gauge and the sensor member are not damaged, and the life of the load sensor can be extended.

[Brief description of drawings]

FIG. 1 is a cross-sectional side view showing a configuration example of a sensor (strain gauge) of a seat weight measuring device according to an embodiment of the present invention.

2A is a plan view of a sensor plate (sensor member) having the sensor of FIG. 1, and FIG. 2B is a circuit diagram of the sensor.

FIG. 3 is a side view schematically showing the overall configuration of the seat weight measuring apparatus according to one embodiment of the present invention.

FIG. 4 is a diagram showing a structure of a seat weight measuring apparatus according to an embodiment of the present invention. (A) is an overall side sectional view, and (B) is a plan view of a sensor plate.

FIG. 5A is a plan view of another sensor plate (sensor member) of the seat weight measuring apparatus according to one embodiment of the present invention,
(B) is a circuit diagram of the sensor.

FIG. 6 is a plan view of still another sensor plate (sensor member) for the seat weight measuring apparatus according to the embodiment of the present invention.

[Explanation of symbols]

1 occupant 2 seat belt 3 seat 4 buckle 5 seat weight measuring device 7 vehicle body (chassis) 10 seat adjuster 11 seat rail 12 anchor fixing part 13 load sensor 15 bending member 17 seat holding mechanism 19 seat fixing part (seat bracket) 21 regulation bar 23 Restriction Block 25 Displacement Restriction Mechanism 30 Sensor 31 Sensor Plate (Spring Material) 32 Insulating Layer (Lower Insulating Layer) 33 Wiring Layer 34 Resistance Layer 35 Insulating Layer (Upper Insulating Layer) 33a, 33b, 33
c, 33d Wiring 34a, 34b, 34c, 34d Strain resistance 34e Sensitivity adjustment resistance 41 Sensor plate 41a Central shaft hole 41b Bolt hole 41c Constricted area 51 Sensor frame upper plate 52 Bolt 53 Sensor frame 55 Bolt 57 Sensor plate 59 Central shaft 61 Washer 63 rubber washer 65 sensor base 67 seat bracket 71 sensor plate 71a central shaft hole 71b bolt hole 81 sensor plate 81a constricted area 81b bolt hole

Continuation of the front page (56) Reference JP-A-10-175503 (JP, A) JP-A-5-141907 (JP, A) JP-A-8-201191 (JP, A) JP-A-6-58706 (JP , A) JP 8-271323 (JP, A) JP 9-269258 (JP, A) JP 9-243436 (JP, A) JP 9-150662 (JP, A) 3-44643 (JP, U) JP 54-41305 (JP, B1) JP 8-12101 (JP, B2) JP 2001-512573 (JP, A) (58) Fields investigated (Int.Cl) . ⁷ , DB name) G01G B60N B60R G01G 19/52 G01G 3/14

Claims (9)

(57) [Claims] 1. A device for measuring seat weight, including the weight of an occupant sitting on a vehicle seat; receiving at least a part of the seat weight inserted in the seat or between the seat and the vehicle body. A load sensor for converting this into an electric signal, wherein the load sensor elastically deforms by receiving at least a part of the seat weight; and a strain gauge arranged on the surface of the sensor member.
The strain gauge includes a lower insulating layer, a wiring layer, a resistance layer, and an upper insulating layer that are sequentially and selectively stacked on the surface of the sensor member, and the lower insulating layer is made of a vitreous material. Displacement regulating mechanism for limiting strain of the strain gauge to 1500 με or less when a load is applied to the load sensor
Is provided, and the displacement regulating mechanism prevents the seat and the seat of the vehicle body from being fixed.
The relative displacement between the two parts is restricted within a certain range between the fixed parts.
Seat weight measuring device characterized in that
Place 2. The seat weight measuring apparatus according to claim 1, wherein the sensor member is made of a material that withstands repeated elastic deformation with an elongation of 0.1% or more. 3. The sheet weight measuring apparatus according to claim 1, wherein each of the layers is formed by applying an insulating material paste, a wiring material paste or a resistance material paste in a certain pattern and then solidifying the applied material. . 4. The seat weight measuring apparatus according to claim 3, wherein the sensor member is made of stainless steel, and each of the layers is solidified by firing. 5. The seat weight measuring apparatus according to claim 1, wherein the connection terminals for connecting the lead wire and the additional component are also laminated. 6. The strain gauge has a strain of 1000 to 1500 μ when a maximum load is applied to the load sensor.
The seat weight measuring device according to any one of claims 1 to 5, wherein? 7. The shape design of the sensor member, the seat weight measuring apparatus can according to claim 1-6 or 1, wherein said surface distortions of the sensor member in the vicinity of the strain gauge is made uniform. 8. The strain gauge comprises a bridge circuit, the seat weight measuring apparatus according to claim 1 to 7, wherein any one of the resistance of the piece is characterized in that it is a 500Omu～5000omu. 9. A seat fixing portion of the seat and the vehicle body
Seat holding with a load sensor and a flexible member connected between
A mechanism is provided, and the measuring member of the load sensor is operated by the action of the flexible member.
Holding mechanism in the range or load bearing range
Claims characterized in that the flexure stroke of the
Item 9. The seat weight measuring device according to any one of items 1 to 8.