JP3680800B2 - Weight measuring device and seat weight measuring device using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a weight measuring device for measuring the weight of an object and a seat weight measuring device using the same.
[0002]
[Prior art]
Automobiles are equipped with seat belts and airbags as devices for ensuring the safety of passengers. Recently, in order to further improve the performance of seat belts and airbags, there is a movement to control the operation of these safety devices according to the weight (weight) and physique of the occupant. For example, the weight of an occupant sitting on a seat to distinguish when a child rides and when an adult rides, to adjust the deployment gas volume and deployment speed of the airbag, or to stop the airbag from operating As an example, a seat weight measuring device that measures a seat weight including the weight of an occupant sitting on a vehicle seat has been proposed (see Japanese Patent Application Laid-Open No. 11-351952). .
[0003]
[Problems to be solved by the invention]
In conventional weight measuring devices and seat weight measuring devices using the same, the load of the object to be measured is directly applied to the sensor substrate that composes the device. However, the sensor output is unstable with respect to the load applied in the direction orthogonal to the load detection direction.
[0004]
The present invention solves this problem and secures a wide dynamic range by reducing the load on the sensor substrate and improving the detection resolution, thereby improving the detection sensitivity and orthogonal to the load detection direction. An object of the present invention is to provide a weight measuring device that realizes the stability of sensor output by reducing the unnecessary load load in the direction and a seat weight measuring device using the same.
[0005]
[Means for Solving the Problems]
In order to solve this problem, the invention according to claim 1 of the present invention includes a leaf spring having a fork-shaped tip and receiving a load at the other end, and an insertion portion for sandwiching the tip of the central arm of the leaf spring. And a sensor board coupled to the fitting pin, and the tips of both end arms of the fork-shaped leaf spring are fixed to the fixed board, respectively, and the sensor board is fixed to the fixed board. This is a measuring device. With this configuration, the sensor board only receives a load that is reduced at a predetermined ratio to the measurement load. Therefore, the load applied to the sensor board is reduced and the detection resolution is improved to ensure a wide dynamic range. At the same time, the detection sensitivity can be improved. In addition, since the tips of both end arms of the fork-shaped leaf spring are fixed to the fixed substrate, unnecessary load load in the direction orthogonal to the load detection direction can be reduced, so that the sensor output stability is improved. It becomes possible to plan.
[0006]
In the invention according to claim 2 of the present invention, the central arm of the leaf spring held by the fitting pin is formed into a straight arm shape, whereby the holding to the fitting pin can be facilitated.
[0007]
In the invention according to claim 3 of the present invention, the center arm of the leaf spring sandwiched between the fitting pins is formed into a divided shape, so that the sandwiching of the fitting pins can be facilitated. Simplification can be facilitated.
[0008]
The invention according to claim 4 of the present invention is transmitted to the sensor substrate by making the width of the central arm of the leaf spring clamped by the fitting pin smaller than the width of both end arms of the fork-shaped leaf spring. It is possible to increase the reduction rate of the load with respect to the input load, improve the detection resolution, secure a wider dynamic range, and improve the detection sensitivity.
[0009]
In the invention according to claim 5 of the present invention, the inner wall surface forming the insertion portion of the fitting pin that sandwiches the central arm of the leaf spring is formed into a semi-cylindrical shape, thereby inserting the middle arm of the leaf spring and the fitting pin. As a result, the moment force generated in the fitting pin can be relaxed, so that the stability of the sensor output with respect to the load can be further enhanced.
[0010]
In the invention according to claim 6 of the present invention, the inner wall surface forming the insertion portion of the fitting pin that sandwiches the central arm of the leaf spring is hemispherical, so that the insertion of the central arm of the leaf spring and the fitting pin is performed. As a result, the moment force generated in the fitting pin can be relaxed, so that the stability of the sensor output with respect to the load can be further enhanced.
[0011]
According to the seventh aspect of the present invention, the load input end side of the leaf spring is divided into three parts so that both side parts and the center part can be bent in opposite directions and can be held by the shaft pin. By adopting a structure having an arm with a mounting hole to the application unit, the leaf spring can be operated in a substantially cantilever manner and unnecessary output due to deflection of the mounting unit in the rotation axis direction can be avoided. It becomes possible.
[0012]
According to an eighth aspect of the present invention, a hemispherical projection is provided on the load input end side of the leaf spring, and the hemispherical projection is arranged so as to sandwich the hemispherical projection, and a mounting hole to the load application portion is provided. With the configuration having the arm, the leaf spring can be operated in a substantially cantilever manner, and unnecessary output due to twisting and deflection applied to the attachment portion can be avoided.
[0013]
According to the ninth aspect of the present invention, it is possible to prevent an excessive load from being applied to the sensor substrate by providing a stopper that regulates the amount of deflection of the leaf spring.
[0014]
According to a tenth aspect of the present invention, a seat weight measuring device according to a tenth aspect of the present invention is configured by attaching the fixed substrate of the weight measuring device to the vehicle body side and the load applying portion below the seat track of the seat at approximately four corners of the vehicle seat. It is configured to measure the seat load and the seat occupant load by the detected load, and by arranging and measuring the weight measuring device at 4 corners with respect to the seat, even if the position of the occupant slightly varies on the seat, An accurate occupant weight can be measured. Here, the weight measuring device measures the weight including the seat and the seat track. However, when only the occupant load is measured, there is no problem if it is calculated in advance or reset.
[0015]
A weight detection device according to an eleventh aspect of the present invention is configured by attaching a fixed substrate of a weight measurement device to an upper portion of a seat track and attaching a load application portion to a lower portion of the seat at approximately four corners of a vehicle seat. It is configured to measure the seat load and seat occupant load based on the detected load, and only the seat weight is initially applied by placing it on the seat track. Since the accuracy can be improved, the detection accuracy of the occupant weight can be increased as a result.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
(Embodiment 1)
Hereinafter, the weight measuring device according to the first embodiment of the present invention will be described with reference to FIGS. 1 to 5 and FIG. 17.
[0017]
1 is an exploded perspective view showing a first embodiment of the present invention, FIG. 2 is a plan view thereof, FIG. 3 is a sectional side view thereof, and FIGS. 4 (a) and 4 (b) are diagrams according to the first embodiment of the present invention. FIG. 5A and FIG. 5B are a front view and a side sectional view of a fitting pin showing still another configuration according to the first embodiment of the present invention. FIGS. 17A and 17B are side views for explaining a vehicle seat incorporating the weight measuring device of the present invention.
[0018]
In the first embodiment, reference numeral 1 denotes a fixed substrate that is fixed to a body to be attached such as the vehicle body 23. The mounting screw portions 4a, 4b, 4c, and 4d for fixing the sensor substrate 2 and the mounting screw portion 4a. Screw holes 12a and 12b for fixing the leaf spring 11 are provided at positions protruding higher than ˜4d.
[0019]
The sensor board 2 uses mounting holes 3a, 3b, 3c, and 3d, and is fixed to mounting screw portions 4a, 4b, 4c, and 4d provided on the fixed board 1 with screws 5a, 5b, 5c, and 5d, and the mounting hole 3a. A hole 6 serving as an action point to which a load is applied is provided at a point where a straight line connecting 3c and 3c and a straight line connecting the mounting holes 3b and 3d intersect. An elongated hole 7 for generating a detectable amount of strain and a strain resistor 8 whose resistance value changes depending on the strain amount are appropriately formed around the hole 6, and the other end of the sensor substrate 2 is strained. A processing circuit 19 is provided for calculating a resistance value change of the resistor 8 and measuring a load.
[0020]
The fitting pin 9 is made of a material having a yield strength equal to or greater than the measurement load, and is provided with a threaded portion 9a at the lower portion and an insertion portion 9b at the head thereof. The fitting pin 9 is passed through the hole 6 of the sensor substrate 2 and fixed with a nut 10.
[0021]
The leaf spring 11 is made of a material having a proof stress equal to or greater than the measurement load like the fitting pin 9, and the central arm 11 c at the tip thereof is inserted into and inserted into the insertion portion 9 b of the fitting pin 9. Further, attachment holes 11a and 11b are provided at the tips of both end arms 11e and 11f of the leaf spring 11, and are fixedly supported in the screw holes 12a and 12b of the fixed substrate 1 by screws 13a and 13b. The insertion portion 9b of the fitting pin 9 and the central arm 11c of the leaf spring 11 are configured to have substantially the same height. Further, the other end of the leaf spring 11 is provided with an attachment hole 11d for attaching to the object to be measured as a load input portion.
[0022]
Next, these assembling methods will be described.
[0023]
First, the fitting pin 9 is fixed to the sensor substrate 2 with the nut 10. Next, the sensor substrate 2 is fixed to the fixed substrate 1 with screws 5a, 5b, 5c, and 5d. Further, the central arm 11c of the leaf spring 11 is inserted and connected to the insertion portion 9b of the fitting pin 9, and attached to the screw holes 12a and 12b of the fixed substrate 1 with screws 13a and 13b through the attachment holes 11a and 11b.
[0024]
Next, this operation will be described.
[0025]
When the load of the object to be measured is applied to the attachment hole 11d as the load input portion of the leaf spring 11 of the weight measuring device incorporated as described above, the load passes through the central arm 11c of the leaf spring 11 attached to the fixed substrate 1. Thus, a force to lift the fitting pin 9 upward is transmitted. Since the fitting pin 9 is attached to the sensor substrate 2, the sensor substrate 2 is distorted by a force for lifting the fitting pin 9 upward. Along with this, the resistance value of the strain resistor 8 changes, and this resistance value change is calculated by the processing circuit 19 to measure the load. Since the tip of the leaf spring 11 has a fork shape and only the central arm 11c is sandwiched between the fitting pins 9, a load reduced at a predetermined ratio to the input load is applied to the sensor substrate 2. Further, the length of the cut portion constituting the fork shape of the leaf spring 11 and the width of the central arm 11 c are changed, or the positions of the mounting holes 11 a and 11 b of the both end arms 11 e and 11 f of the leaf spring 11 and the distance between the fitting pins 9. By appropriately changing, the load applied to the sensor substrate 2 can be reduced to a predetermined ratio.
[0026]
In addition, since the two ends of the both end arms 11e and 11f of the leaf spring 11 are attached to the screw holes 12a and 12b of the fixed substrate 1 with the screws 13a and 13b via the attachment holes 11a and 11b, they are orthogonal to the load detection direction. Since the load in the direction is difficult to be transmitted to the fitting pin 9 and unnecessary output generated by the load in the direction orthogonal to the load detection direction can be suppressed, the load detection accuracy can be improved. Moreover, even if it receives an impact from the direction orthogonal to the load detection direction, the sensor substrate 2 can be prevented from being damaged.
[0027]
Further, the inner wall surface forming the insertion portion 9b of the fitting pin 9 has a semi-cylindrical shape as shown in FIGS. 4 (a) and 4 (b), or a hemispherical shape as shown in FIGS. 5 (a) and 5 (b). As a result, the contact portion between the inner wall surface forming the insertion portion 9b of the fitting pin 9 and the central arm 11c of the leaf spring 11 contacts in a linear or dotted manner to transmit the load, thereby reducing the friction between the two. In addition, since it is possible to suppress transmission of an unnecessary load component due to torsion or the like, it is possible to further improve the stability of the sensor output with respect to the load.
[0028]
Further, since it is unitized as a weight measuring device, for example, even when it is assembled to a vehicle seat, the number of assembling steps can be reduced, and there is no need to adjust sensor characteristics at the time of assembling.
[0029]
FIG. 17 shows an example in which the weight measuring device is mounted between a vehicle seat and a vehicle body. Reference numeral 20 denotes a vehicle seat (for example, a passenger seat), and a seat track 21 is assembled to the lower portion thereof. Reference numeral 22 denotes a weight measuring device, and the leaf spring 11 is fixed to the seat track 21 with bolts and nuts (not shown). On the other hand, although not shown, the fixed substrate 1 is fixed to the vehicle body 23 by bolts and nuts.
[0030]
The weight measuring devices 22 are respectively attached to the front and rear of the seat track 21 so as to correspond to the four corners at the lower end of the vehicle seat 20. In this state, the weight when the occupant is actually seated on the vehicle seat 20 is measured by the four weight measuring devices 22 and subjected to arithmetic processing to determine the weight. At this time, the load of the vehicle seat 20 itself can be corrected by being set in advance or stored in memory. By attaching the weight measuring devices 22 to the front and rear of the seat track 21 so as to correspond to the four corners of the vehicle seat 20, it is possible to discriminate the weight even if the seating position of the occupant slightly changes, and the load The seating position can also be estimated by comparing.
[0031]
Although not shown, the same object can be obtained by assembling the weight measuring device 22 between the seat 20 and the seat track 21. In this case, since the weight of the seat track 21 is not superimposed on the sensor substrate 2, the weight to be corrected is reduced, and the accuracy of calculation and reset performed in advance is improved. As a result, the detection accuracy can be increased.
[0032]
(Embodiment 2)
Hereinafter, a weight measuring apparatus according to Embodiment 2 of the present invention will be described with reference to FIGS.
[0033]
6 is an exploded perspective view showing Embodiment 2 of the present invention, FIG. 7 is a plan view thereof, FIG. 8 is a sectional side view thereof, and FIGS. 9A and 9B are views of Embodiment 2 of the present invention. FIG. 10A and FIG. 10B are a front view and a side view of a fitting pin showing still another configuration in the second embodiment of the present invention. is there.
[0034]
In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, detailed description thereof is omitted, and only different portions will be described in detail.
[0035]
As shown in FIG. 6, the central arm 11c of the leaf spring 11 has a U-shaped split shape, and the insertion portion 9b of the fitting pin 9 that holds the center arm 11c has a U-shaped configuration. This configuration makes it easy to clamp the central arm 11c to the fitting pin 9, simplifies the shape of the fitting pin 9, and facilitates workability.
[0036]
Further, as in the first embodiment, the inner wall surface forming the insertion portion 9b of the fitting pin 9 is shaped like a kamaboko as shown in FIGS. 9 (a) and 9 (b), or FIGS. 10 (a) and 10 (b). In order to transmit the load, the contact portion between the inner wall surface that forms the insertion portion 9b of the fitting pin 9 and the central arm 11c of the leaf spring 11 contacts in a linear or dotted manner. Since the friction between the two can be reduced and the transmission of unnecessary load components due to torsion or the like can be suppressed, it is possible to further enhance the stability of the sensor output with respect to the load.
[0037]
(Embodiment 3)
Hereinafter, a weight measuring apparatus according to Embodiment 3 of the present invention will be described with reference to FIGS.
[0038]
11 is an exploded perspective view showing Embodiment 3 of the present invention, FIG. 12 is a plan view thereof, and FIG. 13 is a sectional side view thereof.
[0039]
In the third embodiment, the same components as those in the second embodiment are denoted by the same reference numerals, detailed description thereof is omitted, and only different portions will be described in detail.
[0040]
As shown in FIG. 11, the load input end side of the leaf spring 11 is divided into three parts, the side parts 11g, 11h and the central part 11i are bent in opposite directions and held by the shaft pin 15, and the shaft pin 15 It has the structure which has the arm 14 provided with the attachment hole 14c to the load application part suspended through the holes 14a and 14b. In addition, elongated holes 17 a and 17 b are provided on the side wall of the fixed substrate 1 for guiding the shaft pin 15 in the vertical direction and for restricting the amount of deflection of the leaf spring 11.
[0041]
In the weight measuring apparatus incorporated in the configuration as described above, the arm 14 to which the weight of the object to be measured is added is supported by the shaft pin 15 through the holes 14a and 14b and can be rotated. Since such a load can always be received in a parallel state and an accurate load can be transmitted to the sensor substrate 2 via the leaf spring 11, unnecessary output due to the deflection of the mounting hole 14c in the rotation axis direction can be avoided. be able to.
[0042]
Further, there is no problem in the normal weight measurement, but there is a concern that the leaf spring 11 may be permanently deformed or damaged, or the sensor substrate 2 may be damaged when a load greater than the maximum measurement load is applied. As a countermeasure, a method of increasing the proof stress of the leaf spring 11 and the sensor substrate 2 can be considered. However, the increase in the proof strength of the leaf spring 11 increases the size of the apparatus. Therefore, it is necessary to reduce the amount of strain in the load, and the measurement resolution is lowered.
[0043]
In order to solve this problem, the long holes 17a and 17b provided on the side wall of the fixed substrate 1 are larger than the diameter of the shaft pin 15 in the vertical direction, and the shaft pin corresponds to the maximum deflection amount of the leaf spring 11 with the maximum measured load. The length 15 is set to a length that can be moved in the vertical direction, and no further movement is possible. As a result, even if a load exceeding the measured maximum load or an impact load is applied, the stopper structure receives the load, so that an excessive load is not applied to the sensor substrate 2 and the sensor substrate 2 or the leaf spring 11 is damaged. Can be prevented.
[0044]
(Embodiment 4)
Hereinafter, a weight measuring apparatus according to Embodiment 4 of the present invention will be described with reference to FIGS. 14 to 16.
[0045]
14 is an exploded perspective view showing Embodiment 4 of the present invention, FIG. 15 is a plan view thereof, and FIG. 16 is a sectional side view thereof.
[0046]
In the fourth embodiment, the same components as those in the second embodiment are denoted by the same reference numerals, detailed description thereof is omitted, and only different portions will be described in detail.
[0047]
As shown in FIG. 14, a hemispherical protrusion 16 is provided on the load input end side of the leaf spring 11. The arm 14 is bent into a substantially box shape, and an attachment hole 14c to the load application unit is provided at the upper part. In addition, ribs 18 a and 18 b having an inverted C shape are provided at the end of the fixed substrate 1. The arm 14 is sandwiched so as to hold a hemispherical protrusion 16 provided on the leaf spring 11, and is arranged substantially in parallel with the inverted rib-shaped ribs 18 a and 18 b provided at the end of the fixed substrate 1.
[0048]
In the weight measuring apparatus incorporated in the configuration as described above, the arm 14 to which the weight of the object to be measured is applied is supported by the hemispherical protrusion 16 provided on the load input end side of the leaf spring 11. Since such a load can always be received at one point, unnecessary output due to twisting or deflection applied to the arm 14 can be avoided.
[0049]
Further, as a stopper structure against a load exceeding the measured maximum load or an impact load, the lower inner surface of the arm 14 and the rib are equal to the maximum deflection amount of the leaf spring 11 at the measured maximum load with respect to the upward displacement of the arm 14. Dimension of the gap between the lower outer surface of the arm 14 and the base surface of the fixed substrate 1 by the maximum amount of deflection of the leaf spring 11 with the maximum measured load for the downward displacement of the arm 14 with respect to the gap between 18a and 18b. Is set to an optimum value. As a result, even if a load exceeding the measured maximum load or an impact load is applied in the vertical direction, the stopper structure receives the load, so that an excessive load is not applied to the sensor substrate 2 and the sensor substrate 2 or Damage to the leaf spring 11 can be prevented.
[0050]
【The invention's effect】
As described above, the present invention provides a leaf spring that has a fork-shaped tip and receives a load at the other end, a fitting pin having an insertion portion for sandwiching the tip of the central arm of the leaf spring, and the fitting pin. The fork-shaped leaf springs are fixed to the fixed substrate, and the sensor substrate is a weight measuring device fixed to the fixed substrate and attached to the object to be measured. The arm is configured to have a stopper structure that does not transmit an unnecessary load due to torsion or deflection and prevents an excessive load from being applied to the sensor substrate.
[0051]
With this configuration, the sensor board is only loaded at a predetermined ratio with respect to the maximum measured load, so detection resolution can be improved, the dynamic range can be increased, detection sensitivity is improved, and load detection is performed. By reducing the load applied in the direction orthogonal to the direction, it is possible to realize the stability of the sensor output.
[0052]
In addition, by restricting the amount of deflection of the leaf spring, it is possible to prevent damage to the sensor substrate and leaf spring even when a load exceeding the maximum measurement load or an abnormal impact load is applied to the object to be measured or the weight measuring device. Therefore, it is possible to provide a safer weight measuring apparatus.
[0053]
Further, since the weight measuring device is unitized, for example, even when assembled on a vehicle seat, the number of assembling steps can be reduced, and it is not necessary to adjust sensor characteristics at the time of assembling.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view showing a first embodiment of a weight measuring device of the present invention. FIG. 2 is a plan view of the same. FIG. 3 is a sectional side view of the same. FIG. 5B is a cross-sectional side view of the fitting pin showing another configuration in FIG. 5A. FIG. 5A is a front view of the fitting pin showing still another configuration according to the first embodiment of the present invention. Fig. 6 is an exploded perspective view showing a second embodiment of the weight measuring device of the present invention. Fig. 7 is a plan view of the same. Fig. 8 is a sectional view of the same side.
(A) Front view of fitting pin showing another configuration in Embodiment 2 of the present invention (b) Side view of the same FIG. 10 (a) Still another configuration in Embodiment 2 of the present invention is shown. FIG. 11 is an exploded perspective view showing Embodiment 3 of the weight measuring device of the present invention. FIG. 12 is a plan view thereof. FIG. 13 is a sectional view of the same side. 14 is an exploded perspective view showing Embodiment 4 of the weight measuring device of the present invention. FIG. 15 is a plan view thereof. FIG. 16 is a side sectional view of the same. FIG. 17 is a vehicle seat incorporating the weight measuring device of the present invention. Side view for explaining [Description of symbols]
DESCRIPTION OF SYMBOLS 1 Fixed board | substrate 2 Sensor board | substrate 3a, 3b, 3c, 3d Mounting hole 4a, 4b, 4c, 4d Mounting screw part 5a, 5b, 5c, 5d Screw 6 Hole 7 Long hole 8 Strain resistor 9 Fitting pin 9a Screw processing part 9b Insertion part 10 Nut 11 Leaf spring 11a, 11b, 11d Mounting hole 11c Central arm 11e, 11f Both end arm 11g, 11h Both side part 11i Central part 12a, 12b Screw hole 13a, 13b Screw 14 Arm 14a, 14b Hole 14c Mounting hole 15 Shaft pin 16 Protrusion 17a, 17b Elongate hole 18a, 18b Rib 19 Processing circuit 20 Seat 21 Seat track 22 Weight measuring device 23 Car body

Claims (11)

A leaf spring that has a fork-shaped tip and receives a load at the other end, a fitting pin having an insertion portion for sandwiching the tip of the central arm of the leaf spring, and a sensor substrate coupled to the fitting pin; A weight measuring device in which the ends of both end arms of the fork-shaped leaf spring are fixed to a fixed substrate, and the sensor substrate is fixed to the fixed substrate. The weight measuring device according to claim 1, wherein the central arm of the leaf spring held between the fitting pins has a straight arm shape. The weight measuring device according to claim 1, wherein the central arm of the leaf spring held between the fitting pins is divided. The weight measuring device according to claim 1, wherein the width of the central arm of the leaf spring held between the fitting pins is narrower than the width of both end arms of the fork-shaped leaf spring. The weight measuring device according to claim 1, wherein an inner wall surface forming an insertion portion of a fitting pin that sandwiches a central arm of a leaf spring has a kamaboko shape. The weight measuring device according to claim 1, wherein the inner wall surface forming the insertion portion of the fitting pin that sandwiches the central arm of the leaf spring is hemispherical. Arm with leaf spring load input end divided into three parts, both sides and center are bent in opposite directions and held by shaft pins, and suspended by this shaft pin and provided with mounting holes for load application The weight measuring device according to claim 1, comprising: 2. The weight measuring device according to claim 1, further comprising an arm provided with a hemispherical protrusion on a load input end side of the leaf spring, and an arm provided with a mounting hole for a load application portion so as to sandwich the hemispherical protrusion. The weight measuring device according to claim 1, further comprising a stopper that regulates a deflection amount of the leaf spring. The weight measurement device according to any one of claims 1 to 9, wherein the fixed board is attached to the vehicle body side and the load application unit is attached to the lower part of the seat track of the seat at approximately four corners of the vehicle seat. Seat weight measurement device that measures seat load and seat occupant load. The fixed board of the weight measuring device according to any one of claims 1 to 9 is configured to be attached to the upper part of the seat track and the load application part to the lower part of the seat at approximately four corners of the vehicle seat. Seat weight measuring device that measures seat load and seat occupant load.

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