JP2002228516A - Weight measuring instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a weight measuring instrument capable of enhancing measurement accuracy. SOLUTION: This weight measuring instrument 3 is equipped with a first electrode 7 displaced by a load from above, a second electrode 8 confronting the first electrode, an electric circuit 11 for measuring capacitance between the first and second electrodes 7 and 8, and a stopper 10 for regulating the displacement of the first electrode 7 to prevent the first electrode 7 from colliding with the second electrode 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a weight measuring device.

[0002]

2. Description of the Related Art For example, some automobile seats have embedded therein a weight measuring device for measuring the weight of an occupant sitting thereon. This type of weighing device is connected to an airbag driving device in order to reliably drive the airbag of the automobile when necessary. For example, JP-A-12-1
Japanese Patent Publication No. 80253 discloses a weight measuring device of this type. The conventional weighing device disclosed in Japanese Patent Application Laid-Open No. 12-180253 is composed of two horizontally arranged electrodes, a spacer arranged between both electrodes,
It is equipped with rivets for integrating two parts. When the weight of the occupant is given to the seat, the gap between the electrodes is reduced, the capacitance between the two is increased, and the weight can be measured.

[0003]

Since the conventional weighing device is constructed as described above, when a large load or impact is applied, the electrodes come into contact with each other, and if the electrodes are damaged or time passes, There have been problems such as deterioration and a decrease in measurement accuracy.

In addition, there has been a problem that the accuracy of measurement is reduced due to a change in ambient temperature or humidity. Furthermore, when the occupant is not strictly seated at a predetermined sitting position, or when the seating posture does not strictly match the predetermined posture, there is a problem that measurement accuracy is reduced.

[0005] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a weighing device capable of improving measurement accuracy.

[0006]

A weighing device according to the present invention comprises a first electrode which is displaced by application of a load;
A second electrode facing the first electrode, a measuring unit for measuring the capacitance between the first electrode and the second electrode, and preventing the first electrode from colliding with the second electrode And a restricting portion for restricting the displacement of the first electrode.

A weighing device according to the present invention measures a first electrode, a second electrode facing the first electrode, and a capacitance between the first electrode and the second electrode. A measurement unit and a load transmitting unit that transmits a load to the first electrode so that the first electrode moves away from the second electrode when a load is applied.

In the weighing device according to the present invention, the load transmitting section contains a sealed fluid, and the pressure of the fluid increased by the load is transmitted to the first electrode.

A weight measuring device according to the present invention is characterized in that a fixed first electrode, a fixed second electrode, an intermediate conductor opposed to the first electrode and the second electrode and displaced by a load. And a measuring unit for measuring a capacitance in a path from the first electrode to the second electrode via the intermediary conductor.

In the weight measuring device according to the present invention, the measuring section is an oscillation circuit whose frequency depends on the capacitance between the first electrode and the second electrode.

A weighing device according to the present invention measures a first electrode, a second electrode facing the first electrode, and a capacitance between the first electrode and the second electrode. A first measuring unit, a load transmitting unit that transmits a load to the first electrode such that the first electrode moves in a direction away from the second electrode when a load is applied, and a third electrode. A fourth electrode facing the third electrode, a second measuring unit for measuring a capacitance between the third electrode and the fourth electrode, a measurement result of the first measuring unit, And a difference detection unit for detecting a difference from the measurement result of the second measurement unit.

[0012] The weight measuring device according to the present invention comprises a first fixed electrode, a second fixed electrode, and a first electrode which faces the first and second electrodes and is displaced by a load. A second conductor from the first electrode through the first conductor
A first measuring unit for measuring capacitance in a path leading to the third electrode, a fixed third electrode, a fixed fourth electrode, and a third electrode and a fourth electrode facing the third electrode and the fourth electrode. A second measuring unit that measures a capacitance in a path from the third electrode to the fourth electrode via the second intermediate conductor via the second intermediate conductor; A difference detection unit that detects a difference between the measurement result of the measurement unit and the measurement result of the second measurement unit.

In the weighing device according to the present invention, when a load is applied, the first intermediate conductor is connected to the first electrode and the second electrode.
And a load transmitting unit for transmitting a load to the first intermediate conductor so as to move in a direction away from the first electrode.

In the weighing device according to the present invention, each of the first measuring unit and the second measuring unit has an oscillation circuit whose frequency depends on a capacitance between the first electrode and the second electrode. It is something that is.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below. Embodiment 1 FIG. FIG. 1 is a front view showing an automobile seat to which the weight measuring device according to Embodiment 1 of the present invention is applied. In the figure, 1 is a seat, 2 is a seat, 3
Is a weighing device. As shown in FIG. 1, a capacitance-type weight measuring device 3 is embedded immediately below a seating surface 2 of an automobile seat 1. In FIG. 1, four weight measuring devices 3 are depicted, but many small devices may be provided, or one large device may be provided as shown in FIG. In addition to the seat surface 2 of the seat 1, one or a plurality of weight measuring devices 3 may be provided on the backrest (not shown).

FIG. 3 is a sectional view of the seat 1 showing details of the weight measuring device 3 according to the first embodiment of the present invention.
In FIG. 3, one weight measuring device 3 is arranged on the seat 1. In the figure, reference numeral 4 denotes a pressure receiving plate (a load transmitting unit),
5 is a projection, 6 is a printed circuit board, 7 is a first electrode, 8 is a second electrode, 9 is a movable plate, 10 is a stopper (regulator),
Reference numeral 11 denotes an electric circuit (a measuring unit, a first measuring unit, and a second measuring unit). As shown in FIG. 3, the weight measuring device 3 includes a pressure receiving plate 4, a protrusion 5, a printed circuit board 6, a first electrode 7,
, The movable plate 9, and the stopper 10. The pressure receiving plate 4 is a flat plate that receives its weight when the occupant is seated. The pressure receiving plate 4 has appropriate rigidity to support the weight of the occupant. A plurality of projections 5 are formed on the lower surface of the pressure receiving plate 4 at appropriate intervals.

Below the pressure receiving plate 4, a flat movable plate 9 is arranged. The pressure receiving plate 4 is arranged so that the protrusion 5 of the pressure receiving plate 4 contacts the upper surface of the movable plate 9.
Is transmitted to the movable plate 9 via the protrusion 5. The movable plate 9 has appropriate rigidity to support the weight of the occupant, and is formed to be appropriately bent when the weight of the occupant is given.

Further, the movable plate 9 is supported on both ends of the printed circuit board 6 by spacers 95. Spacer 9
Reference numeral 5 denotes a support or a wall formed of a rigid body.
May be partially arranged at both end edges of the sheet, or may be arranged over the entire length of both end edges. Further, the spacers 95 may be arranged in front of and behind the paper. The printed circuit board 6 has a substantially flat plate shape, and is supported by a support wall 96 therebelow. The support wall 96 and the printed circuit board 6 form a hollow box so that a space is provided below the printed circuit board 6.

The lower surface of the movable plate 9 has at least one first
Electrodes 7 are arranged. The first electrode 7 has a movable plate 9
May be formed directly, or may be fixed by bonding or other appropriate method. At least one second electrode 8 is opposed to the upper surface of the printed board 6 with a certain distance from the first electrode 7. The second electrode 8 may be formed directly on the printed circuit board 6, or may be fixed by bonding or another appropriate method.

The positions of the electrodes 7 and 8 are preferably closer to the positions of the protrusions 5 of the movable plate 9. Preferably, as shown,
The positions of the electrodes 7 and 8 are directly below the positions of the protrusions 5 of the movable plate 9. Further, the movable plate 9 may be formed of a conductive material, and the movable plate 9 itself may be used as the first electrode. However, the present invention is not intended to be limited to the disclosure of this application, and other arrangements may be made.

On the upper surface of the printed circuit board 6, at least one projection-shaped stopper 10 is provided.
The stopper 10 may be formed integrally with the printed circuit board 6, or may be fixed by welding, bonding, or another appropriate method. The stopper 10 and the printed circuit board 6 have such rigidity that they do not collapse or break even when subjected to an impact caused by the weight of the occupant. Preferably, the position of the stopper 10 is, as shown, the printed circuit board 6.
It is the center of. However, the present invention is not intended to be limited to the disclosure of this application, and other arrangements may be made. Also,
A plurality of stoppers may be provided.

Further, an electric circuit 11 is formed on the lower surface of the printed circuit board 6. The electric circuit 11 is connected to the upper first electrode 7 and the lower second electrode 8, and measures the capacitance between the paired electrodes 7, 8. However, it is not intended that the present invention be limited to the disclosure of this application, and the electrical circuit may be located elsewhere. The electric circuit 11 is preferably an oscillation circuit described later. However, the present invention is not intended to be limited to the disclosure of this application, and other electric circuits may be used.

Next, the operation will be described. Seat seat 1
Is applied to the pressure receiving plate 4 irrespective of whether it is static or dynamic. Since the load applied to the pressure receiving plate 4 is transmitted to the movable plate 9 via the protrusion 5, the movable plate 9 is elastically deformed, bent downward, and the first electrode 7 is also displaced downward. On the other hand, the second electrode 8 provided on the printed board 6 remains stationary without being affected by the displacement of the movable plate 9. Therefore, the distance between the first electrode 7 and the second electrode 8 is reduced, and the capacitance between them is increased. The greater the weight of the occupant, the greater the change in the distance between the electrodes and the greater the change in capacitance, so that the occupant weight can be detected.

When an occupant jumps onto a seat or throws luggage, the movable plate 9 is greatly bent when an excessively large weight is momentarily applied. However, the movable plate 9 comes into contact with the stopper 10 provided on the printed circuit board 6, and the movable plate 9 is not deformed downward, thereby preventing the electrodes facing each other from coming into contact with each other.

As described above, according to the first embodiment, when a weight greater than a certain value is given, the movable plate 9
Are in contact with the stopper 10, and the movable plate 9 is not deformed downward. Therefore, even if an occupant jumps, the opposing electrodes do not come into contact with each other. There is an effect that a malfunction or breakage due to contact is prevented, and the reliability of the device is improved.

Embodiment 2 FIG. FIG. 4 shows seat 1 showing details of weight measuring device 3 according to Embodiment 2 of the present invention.
FIG. In FIG. 4, one weight measuring device 3 is arranged on the seat 1. In the drawing, reference numeral 12 denotes a spring (elastic member). In FIG. 4, the same reference numerals are used to indicate the same components as those in the first embodiment, and description thereof will be omitted.

As shown in FIG. 4, a plurality of springs 12 are arranged between the movable plate 9 and the printed board 6. Spring 12
Are fixed to the movable plate 9 and the printed circuit board 6. Although the illustrated spring is a coil spring, a leaf spring or another suitable spring may be used. No spacer 95 (see FIG. 3) is provided between the movable plate 9 and the printed circuit board 6, and the movable plate 9 is supported only by the spring 12, and is spaced apart from the second electrode 8 by this. They are arranged almost in parallel.

In the first embodiment, the elasticity of the movable plate 9 itself is used to change the capacitance. On the other hand, in the second embodiment, instead of bending of the movable plate 9, the spring 1
The second variant is used. Preferably, one position of the spring 12 is the center of the printed circuit board 6, as shown. However, the present invention is not intended to be limited to the disclosure of this application, and other arrangements may be made. In this embodiment, the movable plate 9 has a high rigidity so as to have a small bending even under a load.

Next, the operation will be described. Seat seat 1
Is applied to the pressure receiving plate 4 irrespective of whether it is static or dynamic. The load applied to the pressure receiving plate 4 is transmitted to the movable plate 9 via the protrusion 5. As a result, the spring 12 is deformed, and the first electrode 7 is also displaced downward. On the other hand, the second electrode 8 provided on the printed circuit board 6
Are not affected by the displacement of the movable plate 9 and remain stationary. Therefore, the distance between the first electrode 7 and the second electrode 8 is reduced, and the capacitance between them is increased. The greater the weight of the occupant, the greater the change in the distance between the electrodes and the greater the change in capacitance, so that the occupant weight can be detected.

When an occupant jumps into a seat or throws luggage, the spring 12 contracts greatly when an excessively large weight is momentarily applied. However, due to the presence of the spring 12, the movable plate 9 is not displaced below the contraction limit of the spring 12, and the opposed electrodes are prevented from contacting each other. Therefore, since the spring 12 also serves as a stopper, there is no need to provide a separate stopper, and the number of parts can be reduced.

As described above, according to the second embodiment, when a weight greater than a certain value is given, the spring 12
Reaches the contraction limit, and the movable plate 9 does not deform downward. Therefore, even if an occupant jumps, the opposing electrodes do not contact with each other, and malfunction. And damage due to contact,
There is an effect that the reliability of the device is improved. Furthermore, since the displacement of the first electrode 7 depends on the elastic deformation of the spring 12, the movable plate 9 hardly bends and moves substantially parallel to the printed circuit board 6, so that the capacitance due to the seating position of the occupant is reduced. Measurement error can be reduced, and accuracy is improved. Also, the first
Since the displacement of the electrode 7 is mainly secured by the elastic deformation of the spring 12, the fatigue of the movable plate 9 on which the first electrode 7 is arranged is reduced.

Embodiment 3 FIG. FIG. 5 shows a seat 1 showing details of a weight measuring device 3 according to Embodiment 3 of the present invention.
FIG. In FIG. 5, one weight measuring device 3 is arranged on the seat 1. In the figure, reference numeral 13 denotes a movable rod (load transmission unit), 17 denotes a first electrode, 18 denotes a second electrode, 19 denotes a movable plate (load transmission unit), 97 denotes a support wall, 11
Reference numeral 5 denotes a projection (a load transmitting portion). In the third embodiment, as shown in FIG.
A projection 115, a printed board 6, a first electrode 17, a second electrode 18, a movable plate 19, a movable bar 13, and a support wall 97 are provided. In FIG. 5, the same reference numerals are used to indicate the components common to the first embodiment, and they will not be described in detail.

The pressure receiving plate 4 and the printed board 6 are supported by a common support wall 97 formed of a rigid body. The edge of the printed board 6 is fitted into a step provided on the support wall 97. The support wall 97 and the printed board 6 constitute a hollow box so that a space is provided below the printed board 6.

The edge of the pressure receiving plate 4 is fixed to an upper portion of the support wall 97. The pressure receiving plate 4 has appropriate rigidity to support the weight of the occupant, and is formed so as to be appropriately bent when the weight of the occupant is given. Both end edges of the pressure receiving plate 4 may be partially supported by the support wall 97, or the entire length of both end edges may be supported by the support wall 97. Pressure plate 4
At least one protrusion 115 is formed on the lower surface of the. In FIG. 5, two projections 115 are depicted,
Without intending to limit the invention to the disclosure of this application, one or more projections 115 may be provided.

FIG. 6 is a partially enlarged view of FIG. In FIG. 6, reference numeral 14 denotes a through hole. At least one second electrode 18 is arranged on the lower surface of the printed circuit board 6. The second electrode 18 may be formed directly on the printed circuit board 6, or may be fixed by bonding or another appropriate method. The position of the second electrode 18 is almost immediately below the position of the protrusion 115 of the pressure receiving plate 4.

The printed circuit board 6 and the second electrode 18 are formed with through holes 14 passing therethrough. The movable rod 13 is inserted into the through hole 14 so as to be movable up and down. The movable rod 13 is vertically oriented by the through hole 14, and a flat movable plate 19 is firmly fixed or integrally formed at the upper end thereof. A first electrode 17 is provided. First
Electrode 17 may be fixed to the movable rod 13,
It does not have to be fixed.

A step is formed on the peripheral portion 17 a of the first electrode 17, and the peripheral portion 17 a is fixed to the lower surface of the printed circuit board 6. The peripheral portion 17a allows the first electrode 1
A gap is provided between the central portion of 7 and the second electrode 18, and both are arranged substantially parallel to each other.

Further, since the peripheral portion 17 a of the first electrode 17 is fixed to the printed circuit board 6, the movable plate 19 supported at the central portion of the first electrode 17 always contacts the projection 115 of the pressure receiving plate 4. Contacting or separated by a small gap. Accordingly, the load applied to the pressure receiving plate 4 when the occupant is seated is transmitted to the first electrode 17 via the protrusion 115 and the movable rod 13, and the first electrode 17 is bent downward. Therefore, the movable bar 13 and the movable plate 19 are formed to have appropriate rigidity to support the weight of the occupant. In addition, the first electrode 17 has appropriate rigidity to support the weight of the occupant, and is formed so as to be appropriately bent when the weight of the occupant is given, and the peripheral edge portion 17a is firmly fixed to the printed circuit board 6. I have.

In the illustrated embodiment, a single through hole 14 is formed, and a single movable rod 13 inserted therein is
Is transmitted to the lower member, a plurality of through holes 14 may be provided, and a plurality of movable bars 13 may be inserted into these.

Next, the operation will be described. Seat seat 1
Is applied to the pressure receiving plate 4 irrespective of whether it is static or dynamic. The load applied to the pressure receiving plate 4 is transmitted to the first electrode 17 via the protrusion 115, the movable plate 19, and the movable rod 13, so that the first electrode 17
Is elastically deformed and bent downward. On the other hand, the second electrode 18 provided on the printed circuit board 6 is not affected by the displacement of the pressure receiving plate 4 and remains stationary. Therefore, the distance between the central portion of the first electrode 17 and the second electrode 18 increases, and the capacitance between the two decreases. The greater the weight of the occupant, the greater the change in distance between the electrodes and the greater the change in capacitance,
The occupant weight can be detected.

When an occupant jumps onto a seat or throws luggage, when the instantaneous excessive weight is given, the first electrode 17 is largely bent. However, according to this configuration, when a load is applied, the distance between the electrodes changes in a direction in which the electrodes widen, so that the electrodes do not come into contact with each other even if an impact such as when an occupant jumps is received. Also,
Even if the first electrode 17 is displaced upward by the reaction, the first electrode 17 and the second electrode 18 do not come into contact with each other.
By providing an interval between 18, the opposing electrodes are prevented from contacting each other. Since the reaction force is smaller than the original impact force due to the damping, the upward displacement is considered to be small.

As described above, according to the third embodiment, the electrodes do not come into contact with each other even if an occupant jumps and receives an impact, so that malfunction or damage due to contact is prevented. There is an effect that the reliability of the device is improved.

Embodiment 4 FIG. FIG. 7 is a sectional view showing details of the weight measuring device 3 according to Embodiment 4 of the present invention. The weight measuring device 3 according to the fourth embodiment has many features in common with the weight measuring device 3 according to the third embodiment.
Has the basic structure shown in FIG. FIG. 7 is an enlarged view of a part of FIG. 5 like FIG. In FIG. 7, the same components as those of the third embodiment are denoted by the same reference numerals, and will not be described in detail. In FIG.
Reference numeral 22 denotes a spring (elastic member).

As shown in FIG. 7, a plurality of springs 22 are arranged between the first electrode 17 and the printed circuit board 6 near the periphery of the first electrode 17. The end of the spring 22 is fixed to the first electrode 17 and the printed board 6, and the first electrode 17 is suspended from the printed board 6 by the spring 22. The first electrode 17 has a peripheral portion 1
7a (see FIG. 6) is not provided, and the first electrode 17a is not provided.
Are supported only by the spring 22 and are arranged substantially parallel to the second electrode 18 at a distance.

In FIG. 7, the first electrode 17 is a spring 22
Is suspended on the printed circuit board 6 by the
The electrode 17 may be placed on a spring to apply a compressive load to the spring. Although the illustrated spring is a coil spring, a leaf spring or another suitable spring may be used.

In the third embodiment, the elasticity of the first electrode 17 itself is used to change the capacitance. On the other hand, in the fourth embodiment, the deformation of the spring 22 is used instead of the bending of the first electrode 17. In this embodiment, the movable plate 9 has a high rigidity so that the movable plate 9 has a small bending even under a load.

Next, the operation will be described. Seat seat 1
Is applied to the pressure receiving plate 4 irrespective of whether it is static or dynamic. The load applied to the pressure receiving plate 4 is transmitted to the first electrode 17 via the protrusion 115, the movable plate 19, and the movable bar 13. Thereby, the spring 2
The first electrode 17 is displaced downward against the second restoring force. On the other hand, the second electrode 18 provided on the printed circuit board 6
Are not affected by the displacement of the pressure receiving plate 4 and remain stationary. Therefore, the distance between the first electrode 17 and the second electrode 18 increases, and the capacitance between the two decreases. The greater the weight of the occupant, the greater the change in the distance between the electrodes and the greater the change in capacitance, and the occupant weight can be detected.

When an occupant jumps into a seat or throws luggage, when the instantaneous excessive weight is given, the first electrode 17 is largely bent. However, according to this configuration, when a load is applied, the distance between the electrodes changes in a direction in which the electrodes widen, so that the electrodes do not come into contact with each other even if an impact such as when an occupant jumps is received. Also,
Even when the first electrode 17 is displaced upward by the reaction, the first electrode 17 is not displaced above the contraction limit of the spring 22, and the opposing electrodes are prevented from contacting each other. Since the reaction force is smaller than the original impact force due to the damping, the upward displacement is considered to be small.

As described above, according to the fourth embodiment, the electrodes do not come into contact with each other even if an occupant jumps and receives an impact, so that malfunction or damage due to contact is prevented. There is an effect that the reliability of the device is improved. Further, since the displacement of the first electrode 17 depends on the elastic deformation of the spring 22, the first electrode 17 hardly bends and moves substantially in parallel with the printed circuit board 6. The measurement error of the capacitance can be reduced, and the accuracy is improved. Further, since the displacement of the first electrode 17 is secured mainly by the elastic deformation of the spring 22, the first electrode 1
7, fatigue is reduced.

Embodiment 5 FIG. 8 is a sectional view showing details of the weight measuring device 3 according to Embodiment 5 of the present invention. The weight measuring device 3 of the fifth embodiment has many features in common with the weight measuring device 3 of the third embodiment.
Has the basic structure shown in FIG. 8 is an enlarged view of a part of FIG. 5 like FIG. In FIG. 8, the same reference numerals are used to indicate the components common to the third embodiment, and they will not be described in detail. In FIG.
Reference numeral 15 denotes an intermediate conductor, 16 denotes a support beam, 23 denotes a support portion, 27 denotes a first electrode, and 28 denotes a second electrode.

As shown in FIG. 8, a first electrode 27 and a second electrode 28 are arranged on the lower surface of the printed circuit board 6. The electrodes 27 and 28 may be formed directly on the printed circuit board 6, or may be fixed by bonding or another appropriate method.

The electrodes 27 and 28 may be arranged in places other than the printed circuit board 6. The electrodes 27 and 28 may be arranged on the same plane perpendicular to the direction of movement of the movable rod 13 in the through hole 14 or may be arranged on a separate plane.

On the upper end of the movable rod 13, a flat movable plate 19 is provided.
Is fixedly or integrally molded, and the movable rod 1
An intermediate conductor 15 is arranged below 3. The intermediary conductor 15 may or may not be fixed to the movable bar 13. At both ends of the intermediary conductor 15, flexible insulating support beams 16 are provided, and the support beams 16 are supported by the insulating support portions 23, respectively. As shown in FIG. 8, the support portion 23 is supported by the printed circuit board 6, but may be supported at another appropriate place.

Since the intermediary conductor 15 is supported in this manner, the intermediary conductor 15 is arranged at a distance from the first electrode 27 and the second electrode 28 and substantially in parallel with the first electrode 27 and the second electrode 28. In addition, since the intermediary conductor 15 is supported in this manner, the movable plate 19 supported at the center of the intermediary conductor 15 is always in contact with the projection 115 of the pressure receiving plate 4 or is provided with a slight gap. is seperated. Therefore,
The load applied to the pressure receiving plate 4 when the occupant is seated
5 and the movable rod 13 are transmitted to the intermediary conductor 15. As shown, a support beam 16 supporting the intermediate conductor 15 is provided.
Has a cross section smaller than that of the intermediary conductor 15, and when a load is applied to the intermediary conductor 15 from above, the support beam 16 is largely bent, and the intermediary conductor 15 is displaced downward. Therefore, the movable bar 13, the intermediate conductor 15, and the support portion 23 are formed to have appropriate rigidity to support the weight of the occupant. The support beam 16 has appropriate rigidity to support the weight of the occupant, and is formed to be appropriately bent when the weight of the occupant is given.

Next, the operation will be described. Seat seat 1
Is applied to the pressure receiving plate 4 irrespective of whether it is static or dynamic. The load applied to the pressure receiving plate 4 is transmitted to the intermediate conductor 15 via the protrusion 115, the movable plate 19, and the movable rod 13. As a result, the intermediate conductor 15 and the support beam 16, particularly the support beam 16, bend, and the intermediate conductor 15 is displaced downward. On the other hand, the electrodes 27 and 28 provided at the printed board 6 or other fixed positions are not affected by the displacement of the pressure receiving plate 4 and remain stationary. Therefore, the distance between the first electrode 27 and the second electrode 28 indirectly increases, and the capacitance between them decreases. The greater the weight of the occupant, the greater the change in the distance between the electrodes and the greater the change in capacitance, so that the occupant weight can be detected.

When an occupant jumps into a seat or throws luggage, the intermediate conductor 15 is greatly bent when an excessively large weight is momentarily applied. However, according to this configuration, when a load is applied, the distance between the electrode 27 or 28 and the intermediary conductor 15 is indirectly increased, so that even if an occupant receives a shock such as when jumping, the electrode 27 or 2 is not affected.
8 and the intermediate conductor 15 do not contact each other. Also,
Even if the first electrode 27 is displaced upward by the reaction, the first electrode 27 and the second electrode 28 do not come into contact with each other.
By providing an interval between the electrodes 28, the opposing electrodes are prevented from contacting each other. Since the reaction force is smaller than the original impact force due to the damping, the upward displacement is considered to be small.

As described above, according to the fifth embodiment, the electrodes and the intermediary conductor do not come into contact with each other even if they receive an impact such as when the occupant jumps, thus preventing malfunction or damage due to contact. This has the effect of improving the reliability of the device. In addition, since both the electrodes 27 and 28 are fixed, it is possible to prevent deterioration and the like due to their bending,
Reliability is further improved. Furthermore, since the intermediate conductor 15 is supported by the support beam 16 which is thinner than that, the fatigue of the intermediate conductor 15 is reduced.

Embodiment 6 FIG. FIG. 9 is a sectional view showing details of the weight measuring device 3 according to Embodiment 6 of the present invention. The weight measuring device 3 of the sixth embodiment has many features in common with the weight measuring device 3 of the fifth embodiment.
Has the basic structure shown in FIG. Like FIG. 8, FIG. 9 is an enlarged view of a part of FIG. In FIG. 9, the same components as those of the fifth embodiment are denoted by the same reference numerals, and will not be described in detail. In FIG.
32 indicates a spring, and 33 indicates a bottom plate.

As shown in FIG. 9, the intermediate conductor 15 is mounted on a spring 32 disposed on a bottom plate 33 of the weight measuring device 3, and a compressive load is applied to the spring 32. I have. The support beam 16 and the support portion 23 are not provided, and the intermediary conductor 15 is supported only by the spring 32, and is disposed substantially parallel to the electrodes 27 and 28 at an interval. Although the illustrated spring is a coil spring, a leaf spring or another suitable spring may be used. In FIG. 9, the intermediary conductor 15 is placed on the spring 32, and a compressive load is applied to the spring 32. Even if the intermediary conductor 15 is hung on the printed circuit board 6 by the spring 32, Good. Although a single spring is provided in the illustrated embodiment, the number of springs may be two or more.

In the fifth embodiment, the elasticity of the intermediate conductor 15 and the support beam 16 is used to change the capacitance. On the other hand, in the sixth embodiment, the deformation of the spring 32 is used instead of the bending of the intermediate conductor 15.

Next, the operation will be described. Seat seat 1
Is applied to the pressure receiving plate 4 irrespective of whether it is static or dynamic. The load applied to the pressure receiving plate 4 is transmitted to the intermediate conductor 15 via the protrusion 115, the movable plate 19, and the movable rod 13. Thereby, the spring 32
, The intermediate conductor 15 is displaced downward. On the other hand, the electrodes 27 and 28 provided at the printed board 6 or other fixed positions are not affected by the displacement of the pressure receiving plate 4,
Stays still. Therefore, the first electrode 27 is indirectly
The distance between the first electrode and the second electrode 28 increases, and the capacitance between the two decreases. The greater the weight of the occupant, the greater the change in the distance between the electrodes and the greater the change in capacitance, so that the occupant weight can be detected.

When an occupant jumps into a seat or throws luggage, for example, when an excessively large weight is applied, the spring 32 is greatly reduced, and the intermediate conductor 15 is largely displaced. However, according to this configuration, when a load is applied, the distance between the electrode 27 or 28 and the intermediary conductor 15 is indirectly increased, so that even if an occupant jumps, the electrode 27 or 28 is subjected to an impact. And the intermediate conductor 15 do not contact each other. In addition, even if the first electrode 27 is displaced upward due to the recoil, the first electrode 27 and the second electrode 28 are opposed to each other by providing a space between the electrodes 27 and 28 so that they do not come into contact with each other. The electrodes are prevented from contacting each other. Since the reaction force is smaller than the original impact force due to the damping, the upward displacement is considered to be small.

As described above, according to the sixth embodiment, the electrodes and the intermediary conductor do not come into contact with each other even if an occupant jumps and receives an impact, thereby preventing malfunction and damage due to contact. This has the effect of improving the reliability of the device. Further, the displacement of the intermediate conductor 15 is
2, the intermediate conductor 15 hardly bends and moves while being substantially parallel to the electrodes 27 and 28. Therefore, the measurement error of the capacitance due to the seating position of the occupant can be reduced, and the accuracy is improved. . Further, since the displacement of the intermediate conductor 15 depends on the elastic deformation of the spring 32, the fatigue of the intermediate conductor 15 is reduced. In addition, since both electrodes 27 and 28 are fixed so as not to be deformed, deterioration due to bending thereof can be prevented, and reliability is further improved.

Embodiment 7 FIG. FIG. 10 is a sectional view showing details of the weight measuring device 3 according to Embodiment 7 of the present invention. The weight measuring device 3 according to the seventh embodiment has many features in common with the weight measuring device 3 according to the third embodiment.
Has the basic structure shown in FIG. FIG. 10 is an enlarged view of a part of FIG. 5 similarly to FIG. In FIG. 10, the same components as those in the third embodiment are denoted by the same reference numerals, and will not be described in detail. In FIG. 10, reference numeral 29 denotes a bag (load transmission unit), and reference numeral 30 denotes an internal space of the bag 29.

In the seventh embodiment, the first electrode 1
7 is hermetically fixed to the printed circuit board 6. That is, the space surrounded by the first electrode 17 and the printed board 6 is hermetically shielded from the external environment except for the through-hole 14 formed in the printed board 6.

An air-tight bag 29 in which air is sealed is disposed above the printed circuit board 6. Bag 29
Are hermetically fixed around the through hole 14. That is, the internal space 30 of the bag body 29 is airtightly shielded from the external environment except for the through holes 14 formed in the printed circuit board 6. Therefore, the internal space 30 of the bag body 29 communicates with the space surrounded by the first electrode 17 and the printed circuit board 6 through the through hole 14, and the bag body 29, the first electrode 17, The substrate 6 constitutes a complete closed body.

By setting the internal pressure higher than the assumed pressure of the external environment, the bag body 29 is inflated and is always in contact with the lower surface of the pressure receiving plate 4 or is separated by a slight gap. . Therefore, the load applied to the pressure receiving plate 4 when the occupant is seated is transmitted to the air in the internal space 30 via the bag body 29. Then, the bag body 29 contracts due to the load, and the air inside flows from the internal space 30 of the bag body 29 through the through hole 14 into the space surrounded by the first electrode 17 and the printed circuit board 6. In this way, the internal pressure of the space increases,
The first electrode 17 bends and is displaced downward. Therefore, the bag body 29 and the first electrode 17 are formed to have strength enough to withstand the pressure caused by the weight of the occupant and to be elastically deformed according to the pressure.

In this embodiment, air is used as the fluid sealed in the space. However, without intending to limit the invention to the disclosure of this application, liquids may be used.

Next, the operation will be described. Seat seat 1
Is applied to the pressure receiving plate 4 irrespective of whether it is static or dynamic. The load applied to the pressure receiving plate 4 is transmitted to the bag body 29. Thereby, the bag body 29,
The internal pressure in the space surrounded by the printed circuit board 6 and the first electrode 17 increases, and the first electrode 17 is displaced downward. On the other hand, the second electrode 18 provided on the printed circuit board 6 is not affected by the displacement of the pressure receiving plate 4 and remains stationary. Therefore, the distance between the first electrode 17 and the second electrode 18 increases, and the capacitance between the two decreases. The greater the weight of the occupant, the greater the change in the distance between the electrodes and the greater the change in capacitance, so that the occupant weight can be detected.

When the occupant jumps into the seat or throws luggage, the bag body 29 contracts greatly when an excessively large weight is momentarily given. However, according to this configuration, when a load is applied, the distance between the electrode 17 and the electrode 18 increases, so that the electrodes 17 and 18 may come into contact with each other even if an occupant jumps and receives an impact. Absent. Further, when the first electrode 17 is displaced upward by the reaction, the air inside acts a buffering action, so that the opposing electrodes are prevented from contacting each other. Since the reaction force is smaller than the original impact force due to the damping, the upward displacement is considered to be small.

As described above, according to the seventh embodiment, the electrodes do not come into contact with each other even if an occupant jumps and receives an impact, and malfunction and damage due to contact are prevented. There is an effect that the reliability of the device is improved. Further, by using such a bag body 29 filled with air, the sitting comfort of the occupant is improved. Further, according to the principle of Pascal, even if pressure is applied to any part of the bag body 29, the same pressure is transmitted to the first electrode 17, and the first electrode 17 is displaced uniquely with respect to the pressure. Is improved. That is, the weight of the occupant can be accurately measured even if the occupant's seating position or posture is not so strictly regulated.

Embodiment 8 FIG. FIG. 11 is a sectional view showing details of the weight measuring device 3 according to Embodiment 8 of the present invention. The weight measuring device 3 of the eighth embodiment is a variation of the weight measuring device 3 of the third embodiment shown in FIG. 6, and FIG. 11 is an enlarged view of a part of FIG. 5 like FIG. . In FIG. 11, the same reference numerals are used to indicate the components common to the third embodiment, and they will not be described in detail.

In FIG. 11, reference numeral 72 denotes a third electrode, 82
Indicates a fourth electrode. In this embodiment, as shown in FIG. 11, a third electrode 72 and a fourth electrode 82 having the same dimensions and the same shape as the first electrode 17 and the second electrode 18 are provided. Similarly to the first electrode 17, the third electrode 7
2 is fixed to the printed circuit board 6, and the second electrode 18
Similarly, the fourth electrode 82 is disposed on the printed circuit board 6. The positional relationship between the third electrode 72 and the fourth electrode 82 is the same as the positional relationship between the first electrode 17 and the second electrode 18. However, the third electrode 72 and the fourth electrode 82
, No load is applied from the pressure receiving plate 4.

The electric circuit 11 includes a first measuring unit for measuring the capacitance between the electrodes 17 and 18, a second measuring unit for measuring the capacitance between the electrodes 72 and 82, A difference detection unit is provided for detecting a difference between the measurement result of the first measurement unit and the measurement result of the second measurement unit. Under such a configuration, the difference detection unit calculates the difference between the capacitance between the first electrode 17 and the second electrode 18 and the capacitance between the third electrode 72 and the fourth electrode 82. This difference is output as a measured value.

Next, the operation will be described. Seat seat 1
When a load is applied to the seating surface 2 of the first electrode 17, a load is applied from the pressure receiving plate 4 to the first electrode 17, similarly to the third embodiment, and a force is applied between the central portion of the first electrode 17 and the second electrode 18. And the capacitance between the two decreases. The first measuring unit measures the capacitance. On the other hand, since no load is applied to the electrode pair of the third electrode 72 and the fourth electrode 82, there should be essentially no change in the distance between the electrodes. The measurement part 2 is the electrode 72,
The capacitance during 82 is measured.

In the measurement of capacitance, displacement or vibration of a member to be fixed, for example, the printed circuit board 6 or other members, temperature, humidity, dew condensation, and the like may have an adverse effect. However, the difference detecting unit detects that the electrode 1
By calculating the difference between the capacitance between the electrodes 7 and 18 and the capacitance between the electrodes 72 and 82, errors due to these adverse effects can be offset.

As described above, according to the eighth embodiment, the displacement or vibration of the member to be fixed, the temperature,
There is an effect that it is possible to cancel a measurement error of capacitance caused by humidity and dew.

Embodiment 9 FIG. 12 is a sectional view showing details of the weight measuring device 3 according to Embodiment 9 of the present invention. The weighing device 3 of the ninth embodiment is a variation of the weighing device 3 of the fourth embodiment shown in FIG. 7, and FIG. 12 is an enlarged view of a part of FIG. 5 like FIG. . In FIG. 12, the same components as those of the fourth embodiment are denoted by the same reference numerals, and they will not be described in detail.

In this embodiment, as shown in FIG. 12, a third electrode 72 and a fourth electrode 82 having the same size and the same shape as the first electrode 17 and the second electrode 18 are provided. . Like the first electrode 17, the third electrode 72 is supported by the spring 22, and like the second electrode 18, the fourth electrode 82 is disposed on the printed circuit board 6. The positional relationship between the third electrode 72 and the fourth electrode 82 is the same as the positional relationship between the first electrode 17 and the second electrode 18. Further, the type, number, position, and other structures of the springs 22 for supporting the electrode 72 are the same as the structure for supporting the first electrode 17. However, no load is applied to the third electrode 72 and the fourth electrode 82 from the pressure receiving plate 4.

Also in this embodiment, the electric circuit 11 includes:
A first measuring unit that measures the capacitance between the electrodes 17 and 18; a second measuring unit that measures the capacitance between the electrodes 72 and 82; and a measurement result of the first measuring unit. And a difference detection unit that detects a difference from the measurement result of the second measurement unit. Under such a configuration, the difference detection unit calculates the difference between the capacitance between the first electrode 17 and the second electrode 18 and the capacitance between the third electrode 72 and the fourth electrode 82. This difference is output as a measured value.

Next, the operation will be described. Seat seat 1
When a load is applied to the seating surface 2, a load is applied from the pressure receiving plate 4 to the first electrode 17, similarly to the fourth embodiment, and a force is applied between the central portion of the first electrode 17 and the second electrode 18. And the capacitance between the two decreases. The first measuring unit measures the capacitance. On the other hand, since no load is applied to the electrode pair of the third electrode 72 and the fourth electrode 82, there should be essentially no change in the distance between the electrodes. The measurement part 2 is the electrodes 72, 8
Measure the capacitance between the two. The difference detection unit is the electrode 1
By calculating the difference between the capacitance between the electrodes 7 and 18 and the capacitance between the electrodes 72 and 82, errors due to the adverse effects of displacement or vibration of the member to be fixed, temperature, humidity, dew condensation, etc. Can be offset.

As described above, according to the ninth embodiment, the displacement or vibration of the member to be fixed, the temperature,
There is an effect that it is possible to cancel a measurement error of capacitance caused by humidity and dew.

Embodiment 10 FIG. FIG. 13 is a sectional view showing details of the weight measuring device 3 according to Embodiment 10 of the present invention. The weight measuring device 3 according to the tenth embodiment is similar to that of FIG.
5 is a variation of the weight measuring device 3 of the fifth embodiment, and FIG. 13 is a partially enlarged view of FIG. In FIG. 13, the same reference numerals are used to designate the same components as those of the fifth embodiment, and they are not described in detail.

In FIG. 13, reference numeral 152 denotes an intermediate conductor;
2 indicates a third electrode, and 282 indicates a fourth electrode. In this embodiment, as shown in FIG. 13, a third electrode 272 having the same dimensions and the same shape as the first electrode 27 and the second electrode 28 is used.
And a fourth electrode 282. Electrode 27
2 and 282 are printed circuit boards 6 like the electrodes 27 and 28.
Are located in Third electrode 272 and fourth electrode 28
2 is the same as the positional relationship between the first electrode 27 and the second electrode 28.

Preferably, the printed circuit board 6 has a through hole 142 formed therethrough, but the through hole 142 may not be formed.

Also, the intermediate conductor 1 for the electrodes 27 and 28
5, the intermediate conductor 15 for the electrodes 272, 282
2 are provided. The structure for supporting the intermediary conductor 152 is similar to the structure for supporting the intermediary conductor 15.
Specifically, flexible support beams 162 are provided at both ends of the intermediate conductor 152, respectively.
62 are supported by the support portions 232 respectively. However, the movable bar 13 and the movable plate 19 are not arranged on the intermediate conductor 152, and a load is applied to the intermediate conductor 152, the third electrode 272, and the fourth electrode 282 from the pressure receiving plate 4. Absent.

Also in this embodiment, the electric circuit 11 includes:
A first measuring unit for measuring the capacitance between the electrodes 27 and 28, and a second measuring unit for measuring the capacitance between the electrodes 272 and 282
And a difference detection unit that detects a difference between the measurement result of the first measurement unit and the measurement result of the second measurement unit. Under such a configuration, the difference detection unit determines the capacitance between the first electrode 27 and the second electrode 28,
Of the capacitance between the second electrode 272 and the fourth electrode 282, and outputs this difference as a measured value.

Next, the operation will be described. Seat seat 1
When a load is applied to the seating surface 2 of the first embodiment, a load is applied to the intermediate conductor 15 from the pressure receiving plate 4 as in the fifth embodiment, and the distance between the electrodes 27 and 28 and the intermediate conductor 15 is increased. The distance between the first electrode 27 and the second electrode 28 indirectly increases, and the capacitance between the two decreases. The first measuring unit measures the capacitance. On the other hand, the third electrode 272
Since no load is applied to the electrode pair of the fourth electrode 282 and the distance between the electrodes, there should be essentially no change in the distance between the electrodes. However, the second measuring unit uses the electrode 272 to cancel the error. , 282 are measured. The difference detector detects the capacitance between the electrodes 27 and 28 and the capacitance between the electrodes 272 and 2.
By calculating the difference between the capacitances 82, errors due to adverse effects of displacement, vibration, temperature, humidity, dew, and the like of a member to be fixed can be canceled.

As described above, according to the tenth embodiment, the displacement or vibration of the member to be fixed, the temperature,
There is an effect that it is possible to cancel a measurement error of capacitance caused by humidity and dew.

Embodiment 11 FIG. FIG. 14 is a sectional view showing details of the weight measuring device 3 according to Embodiment 11 of the present invention. The weight measuring device 3 according to the eleventh embodiment is different from the one shown in FIG.
13 is a variation of the weight measuring device 3 of the tenth embodiment shown in FIG. 3, and FIG. 14 is an enlarged view of a part of FIG. 5 like FIG. In FIG. 14, the same components as those of the tenth embodiment are denoted by the same reference numerals, and will not be described in detail.

In FIG. 14, reference numeral 372 denotes a third electrode, 3
82 indicates a fourth electrode. In this embodiment, FIG.
, The third electrode 372 and the fourth electrode 3 having the same dimensions and the same shape as the first electrode 27 and the second electrode 28.
82 are provided. The electrodes 372 and 382 are arranged on the upper surface of the bottom plate 33 of the weighing device 3 and are located on the opposite side of the electrodes 27 and 28 with the intermediary conductor 15 interposed therebetween. The distance between the third electrode 372 and the fourth electrode 382 with respect to the intermediary conductor 15 is different from the first electrode 2 with respect to the intermediary conductor 15.
7 is the same as the distance between the second electrode 28. However, it is preferable to provide a sufficient interval so that the intervening conductor 15 does not contact the electrodes 372 and 382.

Also in this embodiment, the electric circuit 11 includes:
A first measuring unit that measures the capacitance between the electrodes 27 and 28, and a second measuring unit that measures the capacitance between the electrodes 372 and 382
And a difference detection unit that detects a difference between the measurement result of the first measurement unit and the measurement result of the second measurement unit. Under such a configuration, the difference detection unit determines the capacitance between the first electrode 27 and the second electrode 28,
Of the capacitance between the first electrode 372 and the fourth electrode 382 is obtained, and this difference is output as a measured value.

Next, the operation will be described. Seat seat 1
When a load is applied to the seating surface 2 of the first embodiment, a load is applied to the intermediate conductor 15 from the pressure receiving plate 4 as in the fifth embodiment, and the distance between the electrodes 27 and 28 and the intermediate conductor 15 is increased. The distance between the first electrode 27 and the second electrode 28 indirectly increases, and the capacitance between the two decreases. The first measuring unit measures the capacitance. On the other hand, the third electrode 372
And the electrode pair of the fourth electrode 382, the electrode 37
As a result, the distance between the first electrode 372 and the second electrode 382 is indirectly narrowed, and the capacitance between them is increased. The difference detector detects the capacitance between the electrodes 27 and 28 and the electrode 37.
By calculating the difference in capacitance between 2,382, the displacement or vibration of the member to be fixed, temperature, humidity,
Errors due to the adverse effects of condensation or the like can be offset.

As described above, according to the eleventh embodiment, the displacement or vibration of the member to be fixed, the temperature,
There is an effect that it is possible to cancel a measurement error of capacitance caused by humidity and dew. Further, when the capacitance of one electrode pair increases, the capacitance of the other electrode pair decreases. Therefore, the sensitivity is doubled by obtaining the difference.

Embodiment 12 FIG. FIG. 15 is a sectional view showing details of the weight measuring device 3 according to Embodiment 12 of the present invention. The weighing device 3 according to the twelfth embodiment is similar to that of FIG.
0 is a variation of the weight measuring device 3 of the seventh embodiment, and FIG. 15 is an enlarged view of a part of FIG. 5 similarly to FIG. In FIG. 15, the same reference numerals are used to designate the same components as those in the seventh embodiment, and they will not be described in detail.

Also in this embodiment, the seventh embodiment
Similarly to the above, the bag body 29, the first electrode 17, and the printed circuit board 6 constitute a complete closed body. Also, the first electrode 1
A third electrode 72 and a fourth electrode 82 having the same dimensions and the same shape as the seventh and second electrodes 18 are provided. Like the first electrode 17, the third electrode 72 is fixed to the printed circuit board 6, and like the second electrode 18, the fourth electrode 8
Reference numeral 2 denotes a printed circuit board. Third electrode 72
Is located between the first electrode 17 and the second electrode 82.
Is the same as the positional relationship of the electrode 18. However, no load is applied to the third electrode 72 and the fourth electrode 82 from the pressure receiving plate 4.

Also in this embodiment, the electric circuit 11 includes:
A first measuring unit that measures the capacitance between the electrodes 17 and 18; a second measuring unit that measures the capacitance between the electrodes 72 and 82; and a measurement result of the first measuring unit. And a difference detection unit that detects a difference from the measurement result of the second measurement unit. Under such a configuration, the difference detection unit calculates the difference between the capacitance between the first electrode 17 and the second electrode 18 and the capacitance between the third electrode 72 and the fourth electrode 82. This difference is output as a measured value.

Next, the operation will be described. Seat seat 1
When a load is applied to the seating surface 2 of the first electrode 17, a load is applied to the first electrode 17 from the pressure receiving plate 4, similarly to the third embodiment, and a load is applied And the capacitance between the two decreases. The first measuring unit measures the capacitance. On the other hand, since no load is applied to the electrode pair of the third electrode 72 and the fourth electrode 82, there should be essentially no change in the distance between the electrodes. The measurement part 2 is the electrode 372,
The capacitance between 382 is measured. The difference detection unit obtains the difference between the capacitance between the electrodes 17 and 18 and the capacitance between the electrodes 72 and 82, thereby detecting the displacement or vibration of the member to be fixed, temperature, humidity, and condensation. Errors due to the adverse effects of such factors can be offset.

As described above, according to the twelfth embodiment, the displacement or vibration of the member to be fixed, the temperature,
There is an effect that it is possible to cancel a measurement error of capacitance caused by humidity and dew. Further, when the capacitance of one electrode pair increases, the capacitance of the other electrode pair decreases. Therefore, the sensitivity is doubled by obtaining the difference.

Embodiment 13 FIG. Next, a thirteenth embodiment of the present invention will be described with reference to FIG. The thirteenth embodiment is different from any of the above embodiments in that the electric circuit 11
The present invention relates to an oscillation circuit for measuring an occupant weight, which can be used as a measuring unit, a first measuring unit, or a second measuring unit.
In FIG. 16, reference numerals 117 to 119 denote NOT circuits,
Denotes a fixed resistor, 121 denotes a capacitor, and 122 denotes an output terminal of the oscillation circuit. The NOT circuits 117 to 119 include, for example, a complementary metal oxide semiconductor (CMOS).
tor) an inverter, the output terminal of NOT circuit 117 being connected to the input terminal of NOT circuit 118,
An output terminal 18 is connected to an input terminal of the NOT circuit 119. The output terminal of the NOT circuit 119 is connected to one end of a fixed resistor 120, and the other end of the fixed resistor 120 is connected to the input terminal of a NOT circuit 117. Also, NOT circuit 1
One end of a capacitor 121 is connected to the output terminal
The other end of the capacitor 121 is connected to the input terminal of the NOT circuit 117.

Next, the operation will be described. The voltage generated at the output terminal 122 of the oscillation circuit shown in FIG. 16 has a frequency f represented by the following equation. f = 1 / (2πCxR) = g / (2πεSR) where Cx is the capacitance of the capacitor 121 and R is the resistance of the fixed resistor 120. g is a gap between electrodes when the capacitor 121 is assumed to be a parallel plate capacitor;
ε is the dielectric constant, and S is the area of the electrode. As is apparent from the above equation, the frequency f changes with a change in the capacitance Cx of the capacitor 121 caused by a change in the gap between the electrodes.

The above electrode pair (the pair of electrodes 7 and 8, the electrode 1
7 and 18; a pair of electrodes 27 and 28; a pair of electrodes 72 and 82; a pair of electrodes 272 and 282; and a pair of electrodes 372 and 382). Can be used as an electric circuit in any of the above embodiments. According to such an oscillation circuit, a change in the interval between the electrodes can be easily obtained as a digital output only by counting the number of repetitive waves within a certain time, so that processing by a microcomputer or the like becomes easy. Also, the circuit is very simple, small and inexpensive. However, another oscillation circuit that can obtain a digital output based on a change in the interval between the electrodes may be used.

As described above, according to the thirteenth embodiment, a change in the interval between the electrodes can be easily obtained as a digital output, so that the processing by the microcomputer or the like becomes easy. In addition, there is an effect that the circuit is very simple, small and inexpensive.

[0104]

As described above, according to the present invention, the first electrode displaced by the load, the second electrode facing the first electrode, and the first electrode and the second electrode Since it is configured to include a measuring unit that measures the capacitance between the first electrode and a regulating unit that regulates the displacement of the first electrode in order to prevent the first electrode from colliding with the second electrode, Even if there is a shocking load, the electrodes do not come into contact with each other, malfunctions and damage due to contact are prevented, and the reliability of the device is improved.

According to the present invention, the first electrode, the second electrode facing the first electrode, and the measuring unit for measuring the capacitance between the first electrode and the second electrode When the load is applied, the first electrode is moved in a direction away from the second electrode, so that the first electrode is provided with a load transmitting portion that transmits the load to the first electrode. Even in such a case, the electrodes are prevented from coming into contact with each other, malfunction and damage due to contact are suppressed, and the reliability of the device is improved.

According to the present invention, the load transmitting section contains the sealed fluid, and the pressure of the fluid increased by the load is reduced to the first pressure.
Because the pressure is applied to any part of the fluid by Pascal's principle, the same pressure is transmitted to the first electrode, and the first electrode is unambiguous with that pressure. In this case, there is an effect that the accuracy is improved.

According to the present invention, the fixed first electrode, the fixed second electrode, the intermediate conductor which faces the first and second electrodes and is displaced by a load, And a measuring unit for measuring the capacitance in the path from the first electrode to the second electrode via the intermediary conductor, so that both the first electrode and the second electrode are fixed. Deterioration due to their bending can be prevented,
There is an effect that reliability is further improved.

According to the present invention, the measuring section is configured as an oscillation circuit whose frequency depends on the capacitance between the first electrode and the second electrode. Since the change in the interval between them can be obtained, there is an effect that processing by a microcomputer or the like becomes easy.

According to the present invention, the first electrode, the second electrode facing the first electrode, and the first electrode for measuring the capacitance between the first electrode and the second electrode. A measuring unit, a load transmitting unit that transmits a load to the first electrode such that the first electrode moves in a direction away from the second electrode when a load is applied, a third electrode, and a third electrode. A fourth electrode facing the first electrode, a second measuring unit for measuring a capacitance between the third electrode and the fourth electrode, a measurement result of the first measuring unit, and a second measurement Since it is configured to include a difference detection unit that detects a difference from the measurement result of the unit, it is possible to cancel an error due to an adverse effect of displacement or vibration of a member to be fixed, temperature, humidity, dew, etc. And so on.

According to the present invention, the fixed first electrode, the fixed second electrode, and the first intermediate conductor facing the first electrode and the second electrode and being displaced by a load are provided. ,
A first measuring unit for measuring a capacitance in a path from the first electrode to the second electrode via the first intermediary conductor, a fixed third electrode, and a fixed fourth electrode An electrode, a second intermediate conductor facing and fixed to the third electrode and the fourth electrode, and an electrostatic force in a path from the third electrode to the fourth electrode via the second intermediate conductor. The second measuring unit for measuring the capacitance and the difference detecting unit for detecting the difference between the measurement result of the first measuring unit and the measurement result of the second measuring unit are fixed. There is an effect that errors due to adverse effects of displacement or vibration, temperature, humidity, dew condensation, etc. of a member to be offset can be offset.

According to the present invention, when a load is applied,
Since the first intermediate conductor is provided with the load transmitting portion that transmits the load to the first intermediate conductor so as to move in a direction away from the first electrode and the second electrode, the impact load Even if there is, the intermediary conductor is suppressed from contacting both electrodes, malfunction and damage due to contact are suppressed,
There is an effect that the reliability of the device is improved.

According to the present invention, each of the first measuring unit and the second measuring unit is an oscillation circuit whose frequency depends on the capacitance between the first electrode and the second electrode. With such a configuration, a change in the interval between the electrodes can be easily obtained as a digital output, so that there is an effect that processing by a microcomputer or the like becomes easy.

[Brief description of the drawings]

FIG. 1 is a front view showing an automobile seat to which a weight measuring device according to a first embodiment of the present invention is applied.

FIG. 2 is a front view showing another seat of the automobile to which the weight measuring device according to Embodiment 1 of the present invention is applied;

FIG. 3 is a sectional view of the seat shown in FIG. 2 taken along the line AA for showing details of the weight measuring device according to the first embodiment of the present invention;

FIG. 4 is a sectional view taken along line AA of the seat shown in FIG. 2, showing details of the weight measuring device according to Embodiment 2 of the present invention.

FIG. 5 is a sectional view of the seat shown in FIG. 2 taken along the line AA for showing details of the weight measuring device according to the third embodiment of the present invention.

6 is an enlarged view of a part of FIG.

FIG. 7 is an enlarged cross-sectional view of the weighing device according to Embodiment 4 of the present invention, which is viewed in the same manner as FIG. 6 to show details.

FIG. 8 is an enlarged sectional view similar to FIG. 6, showing details of a weighing device according to Embodiment 5 of the present invention.

FIG. 9 is an enlarged sectional view similar to FIG. 6, showing details of a weight measuring device according to Embodiment 6 of the present invention.

FIG. 10 is an enlarged sectional view similar to FIG. 6, showing details of a weighing device according to Embodiment 7 of the present invention.

FIG. 11 is an enlarged cross-sectional view of a weighing device according to an eighth embodiment of the present invention, which is similar to FIG.

FIG. 12 is an enlarged sectional view similar to FIG. 6, showing details of a weighing device according to Embodiment 9 of the present invention.

FIG. 13 is an enlarged cross-sectional view of the weighing device according to Embodiment 10 of the present invention, viewed in the same manner as FIG.

FIG. 14 is an enlarged sectional view similar to FIG. 6, showing details of a weighing device according to Embodiment 11 of the present invention.

FIG. 15 is an enlarged cross-sectional view similar to FIG. 6, showing details of a weighing device according to Embodiment 12 of the present invention.

FIG. 16 is a circuit diagram showing an oscillating circuit for measuring an occupant weight according to Embodiment 13 of the present invention, which can be used in any of the above embodiments.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Seat seat, 2 Seat surface, 3 Weight measuring device, 4 Pressure receiving plate (Load transmission part), 5 Projection, 6 Printed circuit board, 7
1st electrode, 8 2nd electrode, 9 movable plate, 10 stopper (regulator), 11 electric circuit (measuring unit, 1st measuring unit, 2nd measuring unit), 12 spring (elastic member), 1
Reference Signs List 3 movable rod (load transmitting part), 14 through hole, 15 intermediary conductor, 16 support beam, 17 first electrode, 17a peripheral part, 18 second electrode, 19 movable plate (load transmitting part), 2
2 spring (elastic member), 23 support part, 27 first electrode, 28 second electrode, 29 bag (load transmission part), 3
0 internal space, 32 springs, 33 bottom plate, 72 third electrode, 82 fourth electrode, 95 spacer, 96 support wall, 97 support wall, 115 protrusion (load transmission section), 11
7 to 119 NOT circuit, 120 fixed resistor, 121
Capacitor, 122 output terminal, 152 intermediary conductor, 14
2 through-hole, 162 support beam, 232 support part, 272
Third electrode, 282 Fourth electrode, 372 Third electrode, 382 Fourth electrode.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G01G 23/02 G01G 23/02 A 23/06 23/06 C (72) Inventor Takashi Furui Chiyoda-ku, Tokyo 2-3-2 Marunouchi F-term (reference) in Mitsubishi Electric Corporation 3B087 DE08

Claims (9)

[Claims] 1. A capacitance type occupant weighing device installed on a seat of an automobile and measuring the weight of an occupant, wherein a first electrode displaced by application of a load, and a first electrode facing the first electrode. A second electrode; a measuring unit for measuring a capacitance between the first electrode and the second electrode; and a device for preventing the first electrode from colliding with the second electrode. A weight measurement device comprising: a restriction unit configured to restrict displacement of the first electrode. 2. A first electrode, a second electrode facing the first electrode, a measuring unit for measuring a capacitance between the first electrode and the second electrode, A weight transmitting unit that transmits a load to the first electrode such that the first electrode moves in a direction away from the second electrode when a load is applied. 3. The load transmitting section contains a sealed fluid,
3. The weighing device according to claim 2, wherein the pressure of the fluid increased by the load is transmitted to the first electrode. 4. A fixed first electrode, a fixed second electrode, an intermediate conductor facing the first electrode and the second electrode and being displaced by a load; A measuring unit for measuring a capacitance in a path from the electrode to the second electrode via the intermediary conductor. 5. The measuring unit according to claim 1, wherein the measuring unit is an oscillation circuit whose frequency depends on a capacitance between the first electrode and the second electrode. The weight measuring device according to any one of claims 1 to 4. 6. A first electrode, a second electrode facing the first electrode, and a first measurement for measuring a capacitance between the first electrode and the second electrode. A load transmitting unit that transmits a load to the first electrode so that the first electrode moves in a direction away from the second electrode when a load is applied; a third electrode; A fourth electrode facing the third electrode; a second measuring unit for measuring a capacitance between the third electrode and the fourth electrode; and a measurement result of the first measuring unit And a difference detection unit that detects a difference between the measurement result of the second measurement unit and the measurement result. 7. A fixed first electrode, a fixed second electrode, a first intermediary conductor facing the first electrode and the second electrode and displaced by a load, From the first electrode through the first intermediary conductor, the second electrode
A first measuring unit for measuring a capacitance in a path leading to the third electrode, a fixed third electrode, a fixed fourth electrode, the third electrode and the fourth electrode And the second intermediary conductor fixed to the fourth electrode through the second intermediary conductor from the third electrode.
A second measuring unit that measures capacitance in a path leading to the first electrode, a difference detecting unit that detects a difference between a measurement result of the first measuring unit and a measurement result of the second measuring unit. A weight measuring device comprising: 8. A load transmitting unit for transmitting a load to the first intermediate conductor such that the first intermediate conductor moves in a direction away from the first electrode and the second electrode when a load is applied. The weight measuring device according to claim 7, further comprising: 9. The method according to claim 1, wherein each of the first measuring unit and the second measuring unit is an oscillation circuit whose frequency depends on a capacitance between the first electrode and the second electrode. The weight measuring device according to any one of claims 6 to 8.