WO2006035533A1

WO2006035533A1 - Seat load detecting device

Info

Publication number: WO2006035533A1
Application number: PCT/JP2005/011538
Authority: WO
Inventors: Kiyohiro Fukaya; Yukihiro Kato
Original assignee: Aisin Seiki Kabushiki Kaisha
Priority date: 2004-09-28
Filing date: 2005-06-23
Publication date: 2006-04-06

Abstract

A seat load detecting device for detecting a load acting on a seating portion of a seat of a vehicle etc., in which the seat load detecting device can be made relatively small in size and has excellent detection accuracy. The seat load detecting device has a fixation member (31) fixed to the floor side; a torsion bar (34) connected at its fixation side end section (34a), which is the one end side of the torsion bar (34), to the fixation member (31) and having a horizontal torsion axis (X); an arm member (32) connected to an arm side end section (34b), which is the other end side of the torsion bar (34), and having a load action section (38a), on which a seat load acts, at a position displaced from the torsion axis (X) of the torsion bar (34); and a torsion condition measurement means (50) for measuring a torsion condition of the torsion bar (34). The seat load is detected based on the result of measurement by the torsion condition measurement means (50).

Description

Specification

Seat load detection device

Technical field

The present invention relates to a seat load detection device that detects a seat load that acts on a seating portion of a seat for a vehicle or the like.

Background art

[0002] A veg vehicle that aims to improve safety for passengers such as automobiles has a seat belt holding function depending on whether or not the passenger is seated on the seat, the weight of the seated passenger, etc. In addition, the operation function of the airbag is controlled. In carrying out these controls, it is necessary to accurately detect the seat load, which is the weight of the occupant acting on the seat.

[0003] Then, as such a sheet load detection device, a strain generating plate is provided which is composed of a flat body extending in the horizontal direction and has a strain gauge attached to the surface thereof, and one end side of the strain generating plate is provided. In addition to fixing to the vehicle body side, the other end of the strain plate is fixed to the seat side, and the seat load is detected by the change in the electrical resistance of the strain gauge accompanying the strain of the strain plate. (For example, see Patent Document 1;).

[0004] In addition, a hall element and a magnet are provided as load detection portions on the seat side and the vehicle floor side at predetermined intervals, and the hall element and the magnet are relatively displaced when a load is applied to the seat. by detecting a voltage change generated by, was also the seat load weight detector for detecting seat load (e.g., see Patent Document 2.) ₀

Patent Document 1: Japanese Patent Application Laid-Open No. 2003-83798

Patent Document 2: Japanese Patent Laid-Open No. 2003-97998

Disclosure of the invention

Problems to be solved by the invention

[0005] In the seat load detection device described in Patent Document 1, a flat plate-like strain generating plate extending in the horizontal direction is used, and each end of the strain generating plate is fixed to the vehicle body side and the seat side. For this reason, the horizontal width is relatively large. It becomes a thing. Such an increase in the size of the seat load detection device causes, for example, interference with other devices added to the seat.

Further, since the strain plate receives a relatively large sheet load in a cantilever state, the plate thickness of the strain plate is also relatively thick. The rate of change in the electrical resistance of the strain gauge affixed to the plate may lead to a decrease in detection accuracy.

[0006] Further, in the sheet load detection apparatus using the strain generating plate as described above, the strain state of the strain gauge attached to the surface of the strain generating plate with respect to the sheet load is the distance of the acting point force of the sheet load. Therefore, to improve the sheet load detection accuracy, it is necessary to accurately manage the position where the strain gauge is attached on the surface of the strain plate.

In addition, since the strain state of the strain plate is relatively complicated, the state of change in the electrical resistance of the strain gauge attached to the surface of the strain plate with respect to changes in seat load is relatively complex. As a result, the seat load cannot be detected widely and accurately.

[0007] On the other hand, the seat load detection device described in Patent Document 2 employs a set of hole elements and magnets as a load detection unit, and the displacement due to the sag of the strain generating body is detected relative to the Hall elements and the magnets. It is configured to detect as a displacement.

However, foreign matter such as dust may be brought into the vehicle in which the seat load detection device is installed from outside the vehicle due to people getting on and off. If such foreign matter enters the gap between the Hall element and the magnet and the magnetic field is disturbed, accurate load detection cannot be performed. In addition, if a foreign object is caught in the gap between the Hall element and the magnet, the relative displacement between the Hall element and the magnet is hindered, and the load detection itself cannot be performed.

[0008] The present invention has been made in view of the above-mentioned problems, and its purpose is that it can be relatively miniaturized and has excellent detection accuracy. Furthermore, an important component such as dust is used for load detection. The object is to provide a seat load detection device that can prevent foreign objects from entering.

Means for solving the problem

[0009] In order to achieve the above object, a seat load detection device according to the present invention includes a seat seating portion. A seat load detection device for detecting a seat load acting on a floor, the first characteristic configuration of which is a fixed member fixed to the floor side, and a fixed side end that is one end side fixed to the fixed member. And a torsion bar having a horizontal torsion axis, and a load acting part that is fixed to the arm side end that is the other end of the torsion bar and is displaced from the torsion axis of the torsion bar. An arm member and a torsional state measuring unit for measuring a torsional state of the torsion bar are provided, and the seat load is detected based on a measurement result of the torsional state measuring unit.

That is, for example, a fixing member fixed to the floor side which is the vehicle body side and an arm member fixed to the upper seat side of the vehicle, for example, of the torsion bar having the horizontal twist axis. It is necessary to provide a horizontally extending bracket, etc. compared to a conventional seat load detection device that uses a flat plate-shaped strain plate that extends horizontally by being fixed to both ends. Therefore, it is possible to reduce the size and avoid problems such as interference with other devices added to the sheet.

Furthermore, the twisted state of the torsion bar changes approximately proportionally to the seat load as compared to the squeezed state of the strain generating plate in the conventional seat load detecting device. The seat load can be accurately derived by a relatively simple calculation based on the twisted state of the torsion bar. Furthermore, the ratio of the twisted state to the seat load can be set small to support a relatively wide range of seat loads. It can be made.

Therefore, according to the present invention, it is possible to realize a seat load detection device that can be relatively downsized and has excellent detection accuracy.

[0011] A second characteristic configuration of the seat load detection device according to the present invention is provided with a limiting unit that limits a displacement of the arm member about the torsional axis about a predetermined amount or more with respect to the fixing member.

That is, by providing the limiting means, it is possible to suppress an excessive load from acting on the torsion bar, to suppress damage to the torsion bar, and to further prevent the sheet having the arm member from being fixed. It can be suppressed that the seating portion is greatly displaced with respect to the fixing member and the stability of the seating portion of the seat is lowered. [0013] A third characteristic configuration of the seat load detection device according to the present invention is that the fixing member and the arm member are configured by plate-like bodies facing each other in the horizontal direction.

[0014] That is, the fixing member and the arm member are configured by the plate-like body that is opposed to each other in the horizontal direction, that is, has the torsional axis of the torsion bar as a normal direction. The strength and rigidity of the torsion bar around the torsion axis of the torsion bar can be improved. As a result, damage to each member due to overload and the like can be suppressed, and further, the detection accuracy of the seat load due to the stagnation of each member can be improved. The decrease can be suppressed. Since the installation dimension in the thickness direction of the fixing member and the arm member can be made relatively small, further miniaturization is possible.

[0015] In a fourth characteristic configuration of the seat load detection device according to the present invention, the torsional state measuring means is located at a position where the torsional axis force of the torsion bar is separated from the torsional axis of the arm member relative to the fixing member. It is composed of a displacement sensor that measures the displacement around the twisted state.

That is, since the arm member is displaced around the torsion axis of the torsion bar while keeping the distance to the fixed member substantially constant, the displacement sensor that can be mounted relatively inexpensively and easily as the torsion state measuring means is provided. Thus, the displacement of the arm member with respect to the fixing member can be accurately measured as the torsion state of the torsion bar, and the detection accuracy of the seat load can be further improved.

[0017] In a fifth characteristic configuration of the seat load detection device according to the present invention, the arm member includes at least one of the torsion bar, the load acting unit, and the displacement sensor arranged at positions separated from each other. A member region constituted by a member and connecting the load acting part and the torsion bar and a member region connecting the torsion bar and the displacement sensor transmit force between the two member regions. Is provided in a state of being separated by the torsion bar.

[0018] In this way, when the transmission of force between the two member regions is interrupted by the torsion bar, the member itself connecting the load acting part and the torsion bar is twisted or deformed by the seat load. However, the member area connecting the torsion bar and the displacement sensor can be prevented from being affected by the influence. Therefore, the displacement due to the twist of the torsion bar can be accurately measured by the displacement sensor by suppressing the displacement due to factors other than the torsion of the torsion bar between the torsion bar and the displacement sensor.

[0019] A sixth characteristic configuration of the seat load detection device according to the present invention is that the displacement sensor is provided at a position separated from the load acting portion with respect to the torsional axis of the torsion bar. .

[0020] That is, the displacement of the arm member relative to the fixed member at a position separated from the load acting portion with respect to the torsional axis of the torsion bar is larger than the load acting portion, so that the displacement is shifted to that position. By providing a sensor, the displacement can be accurately measured, and the seat load detection accuracy can be further improved.

[0021] In a seventh characteristic configuration of the seat load detection device according to the present invention, the displacement sensor is configured to measure a direction perpendicular to a torsion axis of the torsion bar in each of the arm member and the fixing member. They are arranged so as to measure displacements in a pair of opposed surfaces facing each other in the linear direction.

That is, the arm member and the fixing member are each formed of a pair of opposing surfaces that are opposed to each other with a direction perpendicular to the torsional axis as a normal direction. Since the distance between them hardly changes, the displacement sensor is arranged so as to measure the displacement on the opposite surface, so that the displacement of the arm member with respect to the fixed member due to torsion of the torsion bar is measured more accurately. be able to.

[0023] In an eighth characteristic configuration of the seat load detection device according to the present invention, the displacement sensor is on a line passing through the torsion center of the torsion bar and perpendicular to the torsion axis! It is in the point arrange | positioned so that the displacement with respect to the said fixing member of a member may be measured.

That is, by measuring the displacement of the arm member with respect to the fixed member on a line passing through the torsion center of the torsion bar and perpendicular to the torsional axis by the displacement sensor, the measured displacement is determined by the torsion bar. The torsion of the torsion bar is almost completely affected by the sag due to the bending moment, and the displacement force can accurately detect the seat load.

[0025] A ninth characteristic configuration of the seat load detection device according to the present invention is the arm of the torsion bar. A cylindrical member that is fixed at one end to a side end and surrounds a side surface of the torsion bar; and the arm member is fixed to the other end of the cylindrical member.

That is, one end side of the cylindrical member surrounding at least a part of the torsion bar is fixed to the arm side end portion of the torsion bar, and the arm member is fixed to the other end side of the cylindrical member. Thus, the distance between the fixing member and the arm member can be made shorter than the length of the torsion bar, and the installation dimension in the thickness direction of the fixing member and the arm member can be further reduced. Furthermore, since the arm member can be arranged near the torsion center (approximately the center in the length direction) of the torsion bar, the arm member on which the seat load acts can be accurately displaced along the torsion bar center. For example, the displacement of the arm member around the torsional axis relative to the fixed member can be accurately measured as a torsion bar in a twisted state.

[0027] In a tenth characteristic configuration of the seat load detection device according to the present invention, the load acting portion is arranged on a line that passes through the torsion center of the torsion bar and is perpendicular to the torsion axis.

[0028] That is, the load acting portion is arranged on a line that passes through the torsion center of the torsion bar and is perpendicular to the torsion axis, thereby suppressing excessive stagnation of the torsion bar due to the seat load acting on the load acting portion. In addition, it is possible to suppress damage due to the stagnation of the torsion bar, and it is possible to suppress a decrease in detection accuracy of the seat load due to the stagnation of the torsion bar.

[0029] In an eleventh characteristic configuration of the seat load detection device according to the present invention, the torsion bar has different cross-sectional shapes in which the second-order moments in a plurality of directions perpendicular to the torsional axis are mutually different. It consists of at least one element.

That is, as described above, the torsion bar is provided with an element having a cross-sectional shape such as a cross shape, a polygonal shape, an elliptical shape, etc. having different cross-sectional second moments in a plurality of directions perpendicular to the torsion axis. 1 or a combination of two or more.

[0031] In a twelfth characteristic configuration of the seat load detection device according to the present invention, a cover member is provided for each of the load acting portion and the torsional state measuring means, and the two cover members are flexible connecting members. It is in the point where it is connected. That is, since the two cover members respectively provided in the load acting portion and the torsional state measuring means are connected by the connecting member, the work efficiency is improved when the cover members are provided at these two locations. Moreover, since the connecting member is flexible, the two cover members can be attached without any inconvenience even when the distance between the load acting portion and the torsional state measuring means is slightly different for each seat load detecting device. Furthermore, by having the flexibility, it can be applied to various types of seat load detection devices in which the arrangement of the load application part and the torsional state measuring means is different, and dust and other foreign substances are difficult to enter. A seat load detection device can be obtained.

[0033] A thirteenth characteristic configuration of the seat load detection device according to the present invention is that a magnetic shielding member is provided on the cover member provided on the twist state measuring means.

That is, since the influence of the external magnetic field can be reduced by providing the magnetic shielding member on the cover member provided in the twist state measuring means, for example, the influence of the magnetic field such as a Hall element and a magnet can be reduced. It is possible to prevent the load detection accuracy from being lowered when the seat load detection device is configured using a sensor.

BEST MODE FOR CARRYING OUT THE INVENTION

An embodiment of a seat load detection device according to the present invention will be described based on the drawings.

FIG. 1 shows a state in which a seat load detection device 30 is attached to a vehicle seat 10. The seat 10 includes a seat cushion 10a as a seating portion and a seat back 10b. When seated, the weight of the seated person acts as a seat load on the seat cushion 10a.

[0037] The seat 10 is provided with seat load detecting devices 30 for detecting the seat load acting on the seat cushion 10a at four positions on the front, rear, left and right of the seat 10, and each seat load detecting device 30 detects the seat load. The sum of the applied loads is detected as the seat load. The sheet load detection device 30 is preferably arranged at four positions as described above in consideration of the stability of the seat 10 and the like, but the number and arrangement positions may be changed as appropriate.

[0038] A lower frame 13 is fixed to the floor side of the vehicle, and the lower frame 13 is The upper frame 12 is held in a slidable state.

The fixing bracket 31 (fixing member) of the seat load detection device 30 is fixed to the upper frame 12, while the arm bracket 32 (arm member) of the seat load detection device 30 is a cushion frame in the seat cushion 10a. It is fixed to 11.

[0039] Further, the seat load detection device 30 disposed in front of the seat 10 and the seat load detection device 30 disposed in the rear of the seat 10 may adopt the same structure except that they are symmetrical in the front-rear direction. it can. Therefore, in the following description, the detailed structure of the seat load detection device 30 disposed behind the seat 10 will be described.

[0040] As shown in Figs. 2 to 4, the seat load detection device 30 includes a fixing bracket 31 as a fixing member fixed to the floor side, and a fixed side end 34a which is one end side of the fixing bracket 31. And a torsion bar 34 having a horizontal twist axis X, and a seat fixed at an arm side end 34b which is the other end of the torsion bar 34 and displaced from the twist axis X of the torsion bar 34 An arm bracket 32 as an arm member having a load acting portion 38a on which a load acts, and a torsional state measuring means 50 for measuring the torsional state of the torsion bar 34, and based on the measurement result of the torsional state measuring means 50 It is configured to detect sheet load.

That is, when the seat load acts on the load acting portion 38a of the arm bracket 32, the torsion bar 34 is twisted according to the seat load. Therefore, the seat is based on the twist state measured by the twist state measuring means 50. The load can be detected

[0041] A cushion frame 11 in the seat cushion 10 is rotatable on the arm bracket 32 by a load pin 38 screwed into a cylindrical limit pin 41 welded and fixed to the arm bracket 32. It is connected in a state, and the position force of the load pin 38 provided with the cushion frame 11 becomes the load acting portion 38a to which the seat load is applied.

Further, the offset amount of the load acting portion 38a, that is, the load pin 38 with respect to the torsion axis X of the torsion bar 34, the torsion strength of the torsion bar 34, and the like take into account the stability of the seat 10 and the measurement accuracy of the torsion state measuring means 50, etc. Set as appropriate.

[0042] The fixed bracket 31 extends upward along a vertical plane, and has an upper floor side. On the other hand, the arm bracket 32 is fixed to the arm side end 34b of the torsion bar 34 in a state of extending sideways along the vertical plane.

The fixed bracket 31 and the arm bracket 32 are formed of plate-like bodies facing each other in the horizontal direction, so that the installation dimension in the thickness direction is relatively small, and further extends along the vertical plane. Easy mounting and shape for arm bracket 32 and upper frame 12.

[0043] Further, a cylindrical member 36 having one end fixed to the arm side end 34b of the torsion bar 34 and surrounding the side surface of the torsion bar 34 is provided, and the arm bracket 32 is provided on the other end of the cylindrical member 36. It is fixed.

That is, by providing the cylindrical member 36, the distance force between the fixing bracket 31 and the arm bracket 32 is shorter than the length of the torsion bar 34, and the installation dimension in the thickness direction of the fixing bracket 31 and the arm bracket 32 is further reduced. Become.

[0044] Furthermore, the inner surface of the cylindrical member 36 and the side surface of the fixed side end 34a of the torsion bar 34 are arranged in a loosely fitted state, and the inner surface of the cylindrical member 36 and the fixed side end 34a of the torsion bar 34 are Excessive stagnation of the torsion bar 34 is suppressed by the contact with the side surface.

Since the inner surface of the cylindrical member 36 and the fixed side end 34a of the torsion bar 34 are each circular, it is easy to process them so that they fit together in a loosely fitted state.

[0045] The torsion bar 34 has a fixed-side end 34a and an arm-side end 34b formed with a relatively large diameter so as to suppress twisting due to the seat load, and a twist caused by the seat load occurs between them. Thus, it is configured as a twisted portion 34c formed with a smaller diameter than the end portions 34a, 34b.

By providing the torsion bar 34 with a twisted portion 34c, it is possible to remove unstable factors such as a change in the twisted state of the torsion bar 34 due to welding when the torsion bar 34 is fixed to the fixed bracket 31 or the arm bracket 32. The torsion bar 34 can be accurately and stably twisted with respect to the seat load.

[0046] Further, the torsion part 34c of the torsion bar 34 is formed to have a cross-sectional shape that protrudes in the vertical direction and the horizontal direction. That is, the section of the torsion bar 34 The torsion bar 34 having such a cross-sectional shape has bending rigidity because the cross-sectional secondary moments in a plurality of directions perpendicular to the twist axis X are formed from elements having different cross-shaped cross-sectional shapes. On the other hand, the torsion bar 34 can be twisted well for seat loads with relatively low torsional rigidity, but it is difficult to bend. The reduction in the strength of the torsion bar 34 can be suppressed by making the cross-sectional shape of the torsion bar 34 a cross shape.

[0047] Further, in the torsion part 34c of the torsion bar 34, the second moment of section along the direction of operation of the seat load, that is, along the vertical direction is larger than the second moment of section along the direction intersecting with the direction of action. It becomes stagnation by the seat load.

[0048] Further, in the cross-shaped cross section of the twisted portion 34c of the torsion bar 34, the width in the vertical direction may be the same as the width in the horizontal direction. By making it larger than the width in the direction, the stagnation of the torsion bar 34 can be further suppressed.

In addition, the cross-sectional shape of the torsion bar 34c of the torsion bar 34 can adopt any shape such as a circle, an ellipse, and a rectangle in addition to the cross shape as described above. A plurality of rod-like bodies arranged in the vertical direction or the like may be used, and the cross-sectional shape thereof may be a plurality of element part forces separated from each other.

[0049] Further, by forming the fixed-side end 34a and the arm-side end 34b of the torsion bar 34 to have a relatively large diameter, the stress generated at each of the ends 34a, 34b can be reduced, and the fixed bracket 31ya. It is possible to suppress breakage of the fixing portion with respect to the arm bracket 32.

The fixed bracket 31 is formed with an opening 42 formed so as to surround the limiting pin 41 protruding from the arm bracket 32. When the limit pin 41 and the opening 42 are subjected to an excessive seat load on the load acting portion 38a, the outer surface of the limit pin 41 contacts the inner surface of the opening 42 and the arm bracket 32 is fixed to the fixed bracket 31. On the other hand, it functions as a limiting means to limit excessive displacement around the twist axis X.

[0051] The torsional state measuring means 50 is configured such that the arm bracket 32 is deformed about the torsion axis X relative to the fixed bracket 31 at a position away from the torsion axis X of the torsion bar 34. The displacement sensor 50a is configured to measure the position as a twisted state, and the displacement sensor 50a is opposed to and fixed to the magnet 52 fixed to the magnet mounting portion 53a provided on the arm bracket 32 side and the magnet 52. The hall element 51 is fixed to a hall element mounting portion 53b provided on the bracket 31 side. Note that the force provided on the side of the fixed bracket 31 that does not displace the hole element 51 that has an electrical connection with the outside, such as an output terminal, and on the side of the arm bracket 32 that displaces the magnet 52 that does not have an electrical connection with the outside. Alternatively, a magnet 52 may be provided on the fixed bracket 31 side, and a hall element 51 may be provided on the arm bracket 32 side.

[0052] Then, when the arm bracket 32 is displaced about the torsional axis X with respect to the fixed bracket 31, the magnet 52 is displaced with respect to the Hall element 51, so that the magnetic flux density measured by the Hall element 51 is reduced. It will change substantially proportional to the amount of displacement.

Therefore, the magnetic flux density is measured as the displacement by the Hall element 51, and the seat load can be detected based on the displacement.

Further, as shown in FIG. 4, the magnet 52 is composed of a pair of magnets 52a and 52b spaced apart from each other by a predetermined amount along the displacement direction, that is, the vertical direction. The other magnet 52b is fixed with the pole facing the hall element 51, and the other magnet 52b is fixed with the north pole facing the hall element 51.

That is, the magnetic flux density distribution formed by the pair of magnets 52a and 52b arranged as described above is, for example, a direction in which the S pole or the N pole is directed toward the Hall element 51 or a direction perpendicular to the direction. Compared with the magnetic flux density distribution formed by one magnet fixed in the direction of the magnetic field, the magnetic flux density change with respect to the displacement is large, so the Hall element 51 measures the displacement as a magnetic flux density change stably and satisfactorily. can do.

The spacing between the pair of magnets 52a, 52b and the spacing between the magnets 52a, 52b and the Hall element 51 are set as appropriate so that the above displacement can be detected well as the magnetic flux density. For example, the pair of magnets 52a, 52b The distance between 52b and 52b is set to about 1.5mm to 2mm, so that the straightness of the magnetic field lines can be improved, and the distance between the magnet 52a, 52b and the Hall element 51 is set to about 2mm. The Hall element 51 can measure the displacement as a change in magnetic flux density.

[0054] Further, each of the magnet 52 and the hall element 51 of the displacement sensor 50a is connected to the torsion bar 34. The arm bracket 32 and the fixed bracket 31 also extend in a direction perpendicular to the torsion axis X so that they face each other. The direction perpendicular to the torsion axis X is the normal direction. It is fixed to the bracket.

That is, the displacement sensor 50a measures the displacement at a pair of opposed surfaces facing each other with the direction perpendicular to the torsion axis X of the torsion bar 34 as the normal direction in each of the arm bracket 32 and the fixed bracket 31. The distance between the magnet 52 and the Hall element 51 is prevented from changing due to, for example, twisting of the arm bracket 32.

[0055] Further, the displacement sensor 50a is arranged to measure the displacement of the arm bracket 32 with respect to the fixed bracket 31 on a line passing through the torsion center XO of the torsion bar 34 and perpendicular to the torsion axis.

That is, it is assumed that the torsion bar 34 is bent by the seat load, so that the arm bracket 32 rotates around an axis that is perpendicular to the torsion axis X and passes through the vicinity of the torsion center XO.

Therefore, by setting the position at which the displacement sensor 50a measures the above displacement on a line that passes through the torsion center XO of the torsion bar 34 and is perpendicular to the torsion axis X, the displacement due to the deflection of the torsion bar 34 at that position can be reduced. Because there is little! /, It is possible to accurately measure the displacement caused by the torsion bar 34 twisting.

[0056] Further, the load acting part 38a is also arranged on a line that passes through the torsion center XO of the torsion bar 34 and is perpendicular to the torsion axis X, so that the torsion bar 34 by the seat load acting on the load acting part 38a It is possible to suppress the stagnation and further the displacement at the measurement position of the displacement sensor 50a due to the stagnation.

In the present embodiment, the cover member 60 can be provided on at least one of the load acting portion 38a and the torsional state measuring means 50. The cover member 60 shown in FIGS. 2 to 4 is configured to integrally cover both the load acting portion 38a and the torsional state measuring means 50. The cover member 60 is appropriately provided with a notch 60 a for avoiding interference with the cushion frame 11 and the fixing bracket 31 according to the mounting position of the cover member 60. The cover member 60 is fixed by, for example, configuring the cover member 60 with an elastic member and fixing brackets. 31 is carried out by the inertia of the cover member 60. Alternatively, the fixing bracket 31 may be fastened together with the mounting hole.

By providing such a cover member 60, dust and other foreign matters can be prevented from entering at least one of the load acting portion 38a and the torsional state measuring means 50, and accurate load detection can be performed over a long period of time. .

[0058] When the torsional state measuring means 50 is a displacement sensor 50a composed of a Hall element 51 and a magnet 52, the cover member 60 can be provided with a magnetic shielding member 70 such as a metal plate. The magnetic shielding member 70 can be provided by press-fitting, fitting, or insert molding into the inner wall of the cover member 60. With the cover member 60 having the magnetic shielding member 70, it is possible to prevent dust and other foreign substances from entering the displacement sensor 50a and at the same time reduce the influence of the external magnetic field applied to the Hall element 51 in particular. A decrease in accuracy can be prevented.

[Another embodiment]

(1)

In the above embodiment, one end side of the cylindrical member 36 is fixed to the arm side end 34b of the torsion bar 34, and the other end side of the cylindrical member 36 is fixed to the arm bracket 32. As shown in FIG. 6, one end side of the cylindrical member 36 may be fixed to the fixed side end portion 34a of the torsion bar 34, and the other end side of the cylindrical member 36 may be fixed to the fixing bracket 31.

[0060] (2)

In the above embodiment, the load pin 38 is provided on the side from which the torsion bar 34 and the cylindrical member 36 protrude, and the position of the load application point 38a passes through the torsion center X0 of the torsion bar 34 and is perpendicular to the torsion axis X. As shown in Figs. 5 and 6, the load pin 38 is provided on the side opposite to the side from which the torsion bar 34 and the cylindrical member 36 protrude, and the load acting point 38a is set to the torsion axis 34 of the torsion bar 34. A position different from the torsion center X0 may be used.

[0061] (3)

In the above embodiment, the cylindrical member 36 is provided. However, as shown in FIGS. 7 and 8, or as shown in FIGS. 9 and 10, the torsion bar 34 without the cylindrical member 36 is directly provided. The arm bracket 32 may be fixed. In this case, the arm bracket 32 is formed in a rectangular shape so as to approach the fixed bracket 31, so that the installation dimension in the thickness direction of the fixed bracket 31 and the arm bracket 32 is reduced.

[0062] (4)

In the above-described embodiment, the arm bracket 32 as an arm member is formed as a single member disposed at a position in which the torsion bar 34, the load acting portion 38a, and the displacement sensor 50a are separated from each other in this order from one end side in the longitudinal direction. The arm bracket 32 as the force arm member is configured by at least one member in which the torsion bar 34, the load acting part 38a, and the displacement sensor 50a are arranged at positions spaced apart from each other, and the torsion bar The force transmission between the two member regions is divided by the torsion bar 34 between the member region connecting 34 and the load acting portion 38a and the member region connecting the torsion bar 34 and the displacement sensor 50a. You can make it in a state!

[0063] For example, as shown in FIGS. 7 and 8, the arm bracket 32 is fixed to a position where the load acting portion 38a, the torsion bar 34, and the displacement sensor 50a are separated from each other in this order from one end side in the longitudinal direction. In the arm bracket 32, a first member region 32a that connects the load application portion 38a and the torsion bar 34, and a second member region that connects the torsion bar 34 and the displacement sensor 50a are provided. A torsion bar 34 is fixed between 32b.

Then, the two member regions of the first member region 32a and the second member region 32b are made different regions in one member, and the force transmission between the two member regions is divided by the torsion bar 34. ! RU

In this manner, by dividing the force transmission between the first member region 32a and the second member region 32b by the torsion bar 34, the first member region 32a itself is deformed if it is twisted by the seat load. Even if it occurs, the second member region 32a can be prevented from being affected, and the displacement due to torsion of the torsion bar 34 can be accurately measured by the displacement sensor 50a.

Further, as shown in FIGS. 9 and 10, the arm bracket 32 has a first arm bracket 32c having one end fixed to the load acting portion 38a and the other end fixed to the torsion bar 34, and one end Is fixed to the torsion bar 34 and the other end is fixed to the displacement sensor 50a. The second bracket 32d is also composed of two members, and the first arm bracket 32c as a member region connecting the torsion bar 34 and the load acting portion 38a, and the member region connecting the torsion bar 34 and the displacement sensor 50a. One end of the second arm bracket 32d is fixed to the torsion bar.

The two member areas are composed of two members, the first arm bracket 32c and the second arm bracket 32d, which are separate from each other, and transmission of force between the two member areas is performed by the torsion bar 34. Configured to sever! RU

In this way, even if the first arm bracket 32c itself is twisted or deformed by the seat load, it is avoided that the second arm bracket 32d separate from the first arm bracket 32c is affected. Thus, the second arm bracket 32d can be prevented from being displaced due to factors other than torsion of the torsion bar 34.

Moreover, since the first arm bracket 32c and the second arm bracket 32d are separate bodies, as shown in FIGS. 7 and 8, the two member regions of the first member region 32a and the second member region 32b are combined into one. The second arm bracket 32d can be reliably prevented from being affected by torsion and deformation of the first arm bracket 32c itself, as compared with a different region of the member.

In FIG. 9 and FIG. 10, the force omitting the limiting pin 41 and the opening 42 functioning as the limiting means shown in the above embodiment, both on the first arm bracket 32c and the second arm bracket 32d. By providing an opening or the like, there may be provided limiting means for limiting excessive displacement of the first arm bracket 32c and the second arm bracket 32d around the twist axis X with respect to the fixed bracket 31. ,.

[0066] In FIGS. 7 and 8, or FIGS. 9 and 10, the load acting portion 38a, the torsion bar 34, and the displacement sensor 50a are arranged in a state of being aligned on the same line along the horizontal direction. The placement positions of the heavy action portion 38a, the torsion bar 34, and the displacement sensor 50a can be changed as appropriate. For example, the load action portion 38a and the torsion bar 34 are arranged in a line on the same line along the horizontal direction. The displacement sensor can also be arranged in a line on the same line along the vertical direction.

[0067] Also in this separate embodiment (4), the cover member 60 can be provided on at least one of the load acting portion 38a and the torsional state measuring means 50. Figures 7 and 8 show the load acting part 3 The cover member 60 which covers 8a and the twist state measuring means 50 separately is shown. 7 and 8 show an example in which the magnetic shielding member 70 is provided on the cover member 60 that covers the torsion state measuring means 50. FIG.

[0068] The cover member 60 of FIGS. 7 and 8 is connected by a flexible connecting member 60b. When the cover member 60 connected by such a connection member 60b is used, the working efficiency is improved when the cover member 60 is provided at two places, that is, the load acting portion 38a and the twist state measuring means 50. Moreover, since the connecting member 60b has flexibility, even if the distance between the load acting portion 38a and the torsional state measuring means 50 is slightly different for each seat load detecting device 30, the two cover members 60 can be connected without inconvenience. Can be attached. Furthermore, by having the flexibility, it can be applied to various variations of the seat load detecting device 30 in which the arrangement of the load acting portion 38a and the torsional state measuring means 50 is different, and dust and other foreign matters enter. It is possible to obtain a seat load detection device 30 that is difficult to insert.

In addition, if the connecting member 60b is provided so as to cover the region between the load acting portion 38a and the torsional state measuring means 50, for example, foreign matter can be prevented from adhering to the torsion bar 34 from above. The seat load detecting device 30 with higher reliability can be obtained.

Although not shown in the drawings, the cover member 60 covering the twisted state measuring means 50 may be configured to mainly block only the gap between the hall element 51 and the magnet 52 from external force. For example, a dust boot made of a flexible member such as rubber can be provided from the magnet mounting portion 53a to the Hall element mounting portion 53b.

9 and 10 also show a cover member 60 that integrally covers both the load acting portion 38a and the torsional state measuring means 50. FIG.

[0069] (5)

In the above-described embodiment, the force of arranging the magnet 52 and the hall element 51 of the displacement sensor 50a so as to face each other in the direction perpendicular to the torsion axis X of the torsion bar 34. For example, The magnet 52 and the hall element 51 may be arranged so as to face each other in a direction parallel to the twist axis X of the torsion bar 34.

[0070] (6) In the above embodiment, the torsional state measuring means 50 is constituted by the displacement sensor 50a. Alternatively, the torsional state measuring means 50 is attached to the side surface of the torsion bar 34 and the distortion state of the side surface of the torsion bar 34 is defined as the twisted state. You may comprise with the strain gauge to measure. That is, the torsion bar torsion changes approximately proportionally to the seat load rather than the distortion of the strain generating plate in the conventional seat load detecting device. Therefore, the strain gauge is used as the torsion state measuring means. Even when affixed to the side of a torsion bar, it is possible to accurately derive the seat load by a relatively simple calculation based on the electrical resistance of the strain gauge while suppressing a decrease in detection accuracy due to a deviation in the affixing position. it can.

When a strain gauge is provided, a circuit for the strain gauge can be provided on the surface of the cylindrical member 36.

Industrial applicability

[0071] The present invention can be applied to various seat load detection devices that detect a seat load acting on a seat of a seat for a vehicle or the like.

Brief Description of Drawings

FIG. 1 is a diagram showing a state in which a seat load detection device is attached to a vehicle seat.

[Fig.2] Perspective view of seat load detection device

[Fig. 3] Plan view of the seat load detection device shown in Fig. 2

圆 4] Elevated view of the seat load detector shown in Fig. 2

FIG. 5 is a perspective view of another embodiment of the seat load detection device.

FIG. 6 is a plan view of the seat load detection device shown in FIG.

FIG. 7 is a perspective view of another embodiment of the seat load detection device.

[Fig. 8] Plan view of the seat load detection device shown in Fig. 7

FIG. 9 is a perspective view of another embodiment of the seat load detection device.

FIG. 10 is a plan view of the seat load detection device shown in FIG.

Explanation of symbols

[0073] 10 seat load detection device

31 Fixing bracket (fixing member)

32 Arm bracket (arm member) a First member region (member region) b Second member region (member region) c First arm bracket (member region) d Second arm bracket (member region) b Arm side end

Torsion par

a Fixed end

Tubular member

a Load application section

Limit pin (limit means) Opening (limit means)

Twist condition measuring means

a Displacement sensor

Cover member

b Connecting member

Magnetic shielding member

Twist axis ''

Twist center

Claims

The scope of the claims

[1] A seat load detection device for detecting a seat load acting on a seat seating portion, wherein a fixing member fixed to a floor side and a fixing side end portion which is one end side are fixed to the fixing member. And a torsion bar having a horizontal torsion axis, and a load acting part which is fixed to the arm side end which is the other end of the torsion bar and where the torsion axis force of the torsion bar is also displaced. A seat load detection device comprising: an arm member; and a torsional state measuring unit for measuring a torsional state of the torsion bar, and detecting the seat load based on a measurement result of the torsional state measuring unit.

[2] The seat load detection device according to [1], further comprising a restricting unit that restricts a displacement of the arm member about a predetermined amount around the torsion axis with respect to the fixed member.

[3] The seat load detection device according to [1] or [2], wherein the fixing member and the arm member are configured by plate-like bodies facing each other in the horizontal direction.

[4] The torsional state measuring means includes a displacement sensor that measures the displacement of the arm member around the torsional axis relative to the fixed member as the twisted state at a position away from the torsional axis of the torsion bar. The seat load detection device according to claim 1.

[5] The arm member is composed of at least one member in which each of the torsion bar, the load acting unit, and the displacement sensor is disposed at a position separated from each other.

A member region connecting between the load acting portion and the torsion bar and a member region connecting between the torsion bar and the displacement sensor divide force transmission between the two member regions by the torsion bar. The seat load detection device according to claim 4, wherein the seat load detection device is provided in a state of being operated.

6. The seat load detection device according to claim 4, wherein the displacement sensor is provided at a position separated from the load acting portion with respect to a torsion axis of the torsion bar.

[7] The displacement sensor includes displacements in a pair of facing surfaces facing each other with the direction perpendicular to the torsional axis of the torsion bar as a normal direction in each of the arm member and the fixing member. 5. The seat load detection device according to claim 4, which is arranged to measure the load.

[8] The displacement sensor is arranged so as to measure a displacement of the arm member with respect to the fixed member on a line passing through the torsion center of the torsion bar and perpendicular to the torsion axis. 4. The seat load detection device according to 4.

[9] The tubular member is provided with a cylindrical member fixed at one end to the arm side end of the torsion bar and surrounding a side surface of the torsion bar, and the arm member is fixed to the other end of the cylindrical member. The seat load detection device described in 1.

10. The seat load detecting device according to claim 1, wherein the load acting part is arranged on a line passing through the torsion center of the torsion bar and perpendicular to the torsion axis.

[11] The seat according to claim 1, wherein the torsion bar is formed of at least one element in which secondary cross-sections in a plurality of directions perpendicular to the twist axis have different cross-sectional shapes. Load detection device.

[12] The seat load according to claim 1, wherein a cover member is provided for each of the load acting portion and the torsional state measuring means, and the two cover members are connected by a flexible connecting member. Detection device.

[13] The seat load detection device according to claim 12, wherein a magnetic shielding member is provided on a cover member provided in the twist state measuring means.