JP2006234420A - Seat load detecting system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a seat load detecting system which can reduce the size relatively, is superior in detection accuracy and capable of continuously maintaining the detection accuracy without causing deformation of constituting member. <P>SOLUTION: The seat load detecting system 1 comprises a swing member 23 positioning close to a junction 31 in the horizontal direction and having a swing force input part 32 where a swing force caused in vertical direction is input when the junction 31 receives a seat load from a seating side member 11, a torsion bar 30 of which the car body side end 30a, a car body side member 20 is fixed, of which the swing side end 30b, swing member 23 is fixed and twisting around the center of twist axis X when the swing force input part 32 swings in vertical direction, and a load detecting means 24 for detecting the seat load based on the displacement around the twist axis X of the swing member 23 measured at the position on the vertical axis of the twist axis X passing through the twist center X0 of the torsion bar 30, and apart from the twist axis X. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a seat load detection device that detects a seat load acting on a seating portion of a vehicle seat.

  In order to improve the safety for passengers of vehicles such as automobiles, the seat belt holding function and the operation of the airbag are determined depending on whether the passenger is seated on the seat or the weight of the seated passenger. Controlling the function is done. In performing these controls, it is necessary to accurately detect the seat load, which is the weight of the passenger acting on the vehicle seat.

  And, as such a seat load detection device, a strain generating plate composed of a flat body extending in the horizontal direction and having a strain gauge attached to the surface is provided, and one end side of the strain generating plate is fixed to the vehicle body side. In addition, it is known that the other end side 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 deflection of the strain plate. (For example, refer to Patent Document 1).

JP 2003-83798 A

In the seat load detecting device described in Patent Document 1, a flat plate-like strain generating plate extending in the horizontal direction is used, and further, a horizontal for fixing each end of the strain generating plate to the vehicle body side and the seat side. Since a bracket or the like extending in the direction is necessary, the width in the horizontal direction is relatively large. Such an increase in the size of the seat load detection device causes interference with other devices added to the vehicle seat, for example.
In addition, since the strain plate receives a relatively large sheet load in a cantilever state, the thickness of the strain plate is also relatively thick. For example, the strain plate is attached to the strain plate with respect to the sheet load. In some cases, the rate of change in the electrical resistance of the attached strain gauge is reduced, leading to a decrease in detection accuracy.

Further, in the sheet load detection device 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 changes depending on the distance from the point of application of the sheet load. In order 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 generating plate.
In addition, since the bending state of the strain plate is relatively complicated, the change state of the electrical resistance of the strain gauge attached to the surface of the strain plate with respect to the change of the sheet load is relatively complicated. Therefore, the seat load may not be detected widely and accurately.

  As an undisclosed seat load detection device invented in view of the above problems, there are devices as shown in the cross-sectional view of FIG. 8 (a) and the side view of FIG. 8 (b). This seat load detection device is fixed to a lower arm 41 as a seating portion side member, and extends to a position spaced horizontally from the lower arm 41, and fixed to the arm bracket 45 at a position spaced horizontally from the lower arm 41. A swing member 53 to be mounted, a torsion bar 60 fixed to the base bracket 50 as a vehicle body side member, and a displacement as load detecting means for detecting the seat load based on the displacement of the swing member 53 relative to the base bracket 50 A sensor 54 is provided.

  In this seat load detecting device, the arm bracket 45 and the lower arm 41 fixed to each other by the connecting bolts 45a and 45b are fixed to the seat cushion, and are configured to be displaced in the vertical direction by the load applied when the occupant is seated. . The base bracket 50 is fixed to an upper rail 42 that constitutes a slide mechanism of the vehicle seat 40. As described above, the seat load detection device is not displaced by being partially fixed to the vehicle body side, and can be displaced by being fixed to the lower arm 41 on the seating portion side.

  The torsion bar 60 twisted about the torsion axis X has a vehicle body side end portion 60 a fixed to the base bracket 50 and a swing side end portion 60 b fixed to the connection portion 53 c of the swing member 53. As a result, the torsion bar 60 is configured to be able to swing the swing member 53 in the vertical direction around the torsion axis X with respect to the fixed base bracket 50. When a seat load is applied to the connecting bolt 53d portion of the swing member 53 via the lower arm 41 and the arm bracket 45, the Hall element portion 55 attached to the swing member 53 is connected to the torsion axis of the torsion bar 60. Swing around X. At this time, since the magnet portion 56 provided opposite to the Hall element portion 55 is fixed to the base bracket 50, the displacement of the Hall element portion 55, that is, the displacement amount of the swing member 53 due to the seat load acting thereon. The amount of change in the magnetic flux density according to is detected in the Hall element portion 55, leading to the derivation of the seat load.

  When an occupant is seated on the vehicle seat 40 on which the seat load detection device is mounted, the seat load caused by the seating is transmitted from the lower arm 41 to the arm bracket 45 at the connecting portions 46 and 47, and further at the swing force input portion 62 at the arm. By transmitting from the bracket 45 to the swing member 53 via the connecting bolt 53d, the swing member 53 swings in the vertical direction. At this time, since the connecting portions 46 and 47 are offset from the swinging force input portion 62 in the horizontal direction, not only the swinging member 53 is swung around the torsion axis X of the torsion bar 60 but also the torsion bar 60. There may be a force acting to move the vehicle body side end portion 60a or the rocking side end portion 60b up and down. In other words, a member that constitutes or supports the seat load detecting device in which a part of the seat load that should be used for swinging the swinging member 53 around the torsional axis X originally acts on the other surface. It may be deformed. Once these members are deformed, an error occurs in the amount of displacement of the swinging member 53 when a seat load is applied, and the detection accuracy cannot be maintained. Further, it is necessary to take subsequent measures such as replacing the deformed member or the sheet body.

  The present invention has been made in view of the above problems, and one of its purposes is to provide a seat load detection device that can be relatively downsized and has excellent detection accuracy. Another purpose is to reliably detect the seat load so that the swinging member swings around the torsional axis, so that the detection accuracy can be maintained continuously without any deformation of the components. The point is to provide a device.

  In order to achieve the above object, the seat load detecting device according to the present invention is characterized by a seat load detecting device for detecting a seat load acting on a seating portion of a vehicle seat, wherein the seating load is fixed to the seating portion side. A portion side member, a vehicle body side member fixed to the vehicle body side, a connecting portion for connecting the seating portion side member, and a position close to the connecting portion in the horizontal direction, When the seat load is received from the seating portion side member, the vehicle body side member is fixed to the swinging member having a swinging force input portion to which the swinging force generated in the vertical direction is input, and the vehicle body side end which is one end side. And a torsion bar that is fixed to a swing side end that is the other end, and that twists about a horizontal twist axis when the swing force input portion swings in the vertical direction, and the torsion Through the twist center of the bar And the seat based on a displacement around the torsional axis of the swinging member with respect to the vehicle body side member measured at a position spaced from the torsional axis on a line perpendicular to the torsional axis. And a load detecting means for detecting a load.

According to the above characteristic configuration, the swinging member is located at the connecting portion for connecting to the seating portion side member and the position close to the connecting portion in the horizontal direction, and receives a seat load from the seating portion side member at the connecting portion. A torsion bar is provided with a swinging force input portion to which a swinging force generated in the vertical direction is input, and the vehicle body side member is fixed to the vehicle body side end portion which is one end side, and is the other end side. When the swinging member is fixed to the swinging side end, and the swinging force input unit swings in the vertical direction, the swinging movement moves about the horizontal twist axis, and the load detection means passes through the torsion center of the torsion bar. In addition, the seat load is detected based on the displacement around the torsion axis of the swing member relative to the vehicle body side member measured at a position on the line perpendicular to the torsion axis and away from the torsion axis. Become.
That is, in the seat load detection device of the present invention, the swinging force that swings the swinging force input portion in the vertical direction is such that the seat load applied from above to the connecting portion connected to the seating portion side member swings from the connecting portion. It is transmitted to the power input unit in the horizontal direction. At this time, the swinging force input part is in a position close to the connecting part in the horizontal direction, that is, the swinging force input part is at a position that is hardly offset from the connecting part. There is almost no moment to rotate. Therefore, when a seat load is applied to the connecting portion, the seat load is efficiently transmitted to swing the swing member around the torsion axis of the torsion bar, and hardly acts on other members. As a result, the other members are not deformed by the seat load, and the seat load detection device can be continuously used with good detection accuracy.
Also, compared to the seat load detection device having the other configuration described above, parts such as arm brackets are not required, so that the number of parts and parts cost can be reduced, and the seat load detection device can be reduced in size and weight. .

  Another characteristic configuration of the seat load detection device according to the present invention is that the swinging member and the seating portion are directed from the vehicle body side member fixed to the vehicle body side end portion of the torsion bar toward the protruding direction of the torsion bar. Side members are arranged in order, and the swinging member includes a swinging portion swinging in a vertical direction, and protruding from the swinging portion in the same direction as the protruding direction, the swinging portion and the torsion bar A connecting portion is provided to connect the swing side end, and at least one of the swing member and the seating portion side member is bent in a direction away from each other.

  According to the above characteristic configuration, the load detecting means passes through the torsion center of the torsion bar and is on the line perpendicular to the torsion axis and spaced from the torsion axis. While configured to measure the displacement of the rocking member around the torsion axis, at least one of the rocking member and the seating portion side member can be arranged avoiding the torsion bar.

  Still another characteristic configuration of the seat load detection device according to the present invention is that the connection portion is inserted into a through hole provided in the seating portion side member with a gap in the vertical direction.

  According to the above characteristic configuration, since the connecting portion is inserted into the through hole provided in the seating portion side member with a gap in the vertical direction, even if a large swinging force is applied to the swinging member, the edge of the connecting portion and the through hole is provided. The part comes into contact. As a result, the amount of displacement of the connecting portion is regulated by the contact of both, so that when the amount of displacement of the connecting portion increases without limit, the other members connected to the swing member are greatly displaced. It is possible to suppress the occurrence of problems such as deformation.

A seat load detection device according to the present invention will be described below with reference to the drawings.
FIG. 1 is a view showing a state in which a seat load detection device 1 according to the present invention is attached to a vehicle seat 10.
The vehicle seat 10 includes a seat cushion 10a as a seating portion and a seat back 10b as a backrest portion. When the occupant sits on the vehicle seat 10, the weight of the occupant is added to the seat cushion 10a, and the seat load detection device 1 detects the seat load. Inside the seat cushion 10a, plate-like lower arms 11 as seating portion side members are provided one by one on both side surfaces below the vehicle seat 10. The seat load detection device 1 is provided at a total of four locations on the front side and the rear side of each lower arm 11.

The seat load detection device 1 provided on the front side of the vehicle seat 10 and the seat load detection device 1 provided on the rear side have the same configuration except that they are symmetrical in the front-rear direction. Accordingly, in the following description, the configuration of the seat load detection device 1 provided on the front side of the vehicle seat 10 will be described with reference to FIGS. 1 to 6, and the configuration of the seat load detection device 1 provided on the rear side will be described. Description is omitted.
FIG. 2 is an enlarged side view of the seat load detection device 1 of the present invention. FIG. 3 is a cross-sectional view of the seat load detection device. FIG. 4 is a longitudinal sectional view taken along line BB in FIG. FIG. 5 is a longitudinal sectional view taken along line CC in FIG. FIG. 6 is a vertical sectional view taken along line DD in FIG.

  The seat load detection device 1 is fixed to a lower arm 11 as a seating portion side member and a base bracket 20 as a vehicle body side member. The seat load detection device 1 then determines the seat load based on the swing member 23 connected to the lower arm 11, the torsion bar 30 fixed to the base bracket 20, and the displacement of the swing member 23 relative to the base bracket 20. A displacement sensor 24 is provided as load detecting means for detecting.

  In the seat load detection device 1, the lower arm 11 is connected to the seat cushion 10 a and is configured to be displaced in the vertical direction by the applied load. The base bracket 20 is fixed to the upper rail 12 constituting the sliding mechanism of the vehicle seat 10 using bolts 35 and nuts 36. The upper rail 12 is slidably attached to the lower rail 13 fixed to the floor of the vehicle body. As described above, part of the seat load detection device 1 is not displaced by being fixed to the vehicle body side, and the other part is fixed to the lower arm 11 on the seating portion side and can be displaced.

  As shown in FIGS. 3 to 6, the torsion bar 30 constituting the seat load detection device 1 has a base bracket 20 fixed to a vehicle body side end portion 30 a which is one end side, and a swing side end portion which is the other end side. The swing member 23 is fixed to 30b. The torsion bar 30 has a horizontal twist axis X, and twists about the twist axis X when the swing member 23 swings in the vertical direction. The cross-sectional shape of the portion other than the vehicle body side end 30a and the swinging side end 30b of the torsion bar 30 can be various as long as the torsion bar 30 is twisted about the twist axis X. . For example, a circular shape, an elliptical shape, a rectangular shape, a cross shape, or the like may be used, or a shape in which a plurality of rod-shaped bodies are bundled.

  The swinging member 23 constituting the seat load detecting device 1 protrudes from the swinging part 23b in the same direction as the swinging part 23b swinging in the vertical direction and the protruding direction of the torsion bar 30 from the base bracket 20, A connecting portion 23c is provided for connecting the swinging portion 23b and the swinging end 30b of the torsion bar 30. The swinging portion 23b of the swinging member 23 is formed in a plate shape, and is connected to the connecting portion 23c in the vicinity of the torsion bar 30. Further, one end side of the connection portion 23 c of the swing member 23 is connected to the swing side end portion 30 b of the torsion bar 30, and the other end side is connected to the swing portion 23 b of the swing member 23. The connection portion 23c of the present embodiment is configured in a cylindrical shape that can surround the periphery of the torsion bar 30.

  The displacement sensor 24 serving as a load detecting means constituting the seat load detecting device 1 is provided on a line passing through the torsion center X0 of the torsion bar 30 and perpendicular to the torsion axis X. The displacement sensor 24 is configured to detect the seat load based on the displacement around the torsion axis X of the swing member 23 relative to the base bracket 20 measured at a position separated from the torsion axis X. In the example of the present embodiment, the displacement sensor 24 is provided on the swing part 23b of the swing member 23, and the hall element part 25 having the hall element 25a and the magnet part 26 having the magnet 26a provided on the base bracket 20. With. The hall element portion 25 is attached to the swing portion 23b with screws 27, and the magnet portion 26 is attached to the base bracket 20 with screws 28 and 29.

  That is, in the horizontal direction, the center position of the Hall element 25a and the center position of the magnet 26a are on a line that passes through the twist center X0 of the torsion bar 30 and is perpendicular to the twist axis X. When the swinging member 23 swings in the vertical direction about the torsional axis X of the torsion bar 30, the positional relationship between the Hall element 25a and the magnet 26a changes (displaces), and is measured by the Hall element 25a. The magnetic flux density also changes approximately proportionally to the amount of displacement. Therefore, the magnetic flux density is measured by the Hall element section 25, and the signal processing means (not shown) connected to the Hall element 25a converts the magnetic flux density into a displacement, and the seat load is detected based on the displacement. It will be.

  As described above, the position at which the displacement sensor 24 measures the swing displacement of the swing member 23 is on a line that passes through the twist axis X of the torsion bar 30 and is perpendicular to the twist axis X. The oscillating displacement measured by the displacement sensor 24 is hardly affected by the bending due to the bending moment of the torsion bar 30. As a result, the swing displacement measured by the displacement sensor 24 accurately reflects the displacement caused by the swing of the swing member 23 around the torsion axis X of the torsion bar 30, and the sheet is accurately determined from the displacement. The load can be detected.

  The swing member 23 is connected to the lower arm 11 by a connecting bolt 23d. A protruding portion 23a (for example, a weld nut or the like) surrounding the connecting bolt 23d is provided for the swinging portion 23b. At this time, a portion that is a contact point between the connecting bolt 23 d and the lower arm 11 and where a seat load acts from the lower arm 11 to the swing member 23 is defined as a connecting portion 31. Further, the intersection of the swing surface and the connecting bolt 23d when the plate-like swing portion 23b swings in the vertical direction is defined as a swing force input portion 32.

  In the seat load detection device 1 according to the present invention, the connecting portion 31 and the swinging force input portion 32 are in a position close to each other in the horizontal direction, that is, the offset from the lower arm 11 to the swinging member 23 is almost zero. Although a vertical swinging force about the torsional axis X of the torsion bar 30 acts on the member 23, no other unexpected force acts on the member 23. That is, when a seat load is applied to the connecting portion 31, the seat load is efficiently transmitted to swing the swinging member 23 around the torsion axis X of the torsion bar 30, and almost to other members. Does not work. Therefore, even if a large seat load acts on the lower arm 11 and is transmitted to the swing member 23, the problem that other members such as the lower arm 11 and the base bracket 20 are deformed does not occur.

  Further, the protrusion 23 a of the swing member 23 is inserted in a state of being surrounded with a vertical gap with respect to the first hole 21 that penetrates the base bracket 20. That is, the protrusion 23 a and the edge of the first hole 21 are configured to contact each other when the amount of vertical displacement of the protrusion 23 a of the swing member 23 increases. Therefore, even if a large seat load is applied to the lower arm 11, it is possible to prevent the swinging member 23 from excessively swinging in the vertical direction.

  As shown in FIGS. 3 to 6, the swinging member 23 and the lower arm 11 are sequentially arranged from the base bracket 20 toward the protruding direction of the torsion bar 30. The swing member 23 and the base bracket 20 are bent in a direction away from the lower arm 11. Specifically, the swinging portion 23 b of the swinging member 23 is located close to the lower arm 11 at the position of the swinging force input portion 32. On the other hand, the oscillating portion 23b of the oscillating member 23 is bent at a position connected to the connecting portion 23c so that the oscillating portion 23b is at a position separated from the distance between the oscillating force input portion 32 and the lower arm 11. ing.

  Further, the lower arm 11 is provided with a second hole portion 33 as a through hole, and the connecting portion 23c of the swing member 23 is inserted into the second hole portion 33 with a predetermined amount of gap in the vertical direction. That is, when a large force is applied to the lower arm 11 and the second hole 33 of the lower arm 11 is to be displaced largely in the vertical direction, the second arm 33 of the lower arm 11 is fixed to the swing side end 30b of the torsion bar 30 that is not so displaced. Abutting on the connecting portion 23c of the moving member 23, the displacement is limited. Therefore, when a large seat load is applied to the lower arm 11, the swing member 23 (swing force input portion 32) moves other than swinging in the vertical direction about the torsion axis X of the torsion bar 30 (for example, The above-described movement of the lower arm 11 that is largely displaced in the vertical direction is limited.

  In addition, the swing member 23 and the base bracket 20 are bent in a direction away from the lower arm 11 and the connecting portion 23c of the swing member 23 is inserted into the first hole 21 of the lower arm 11. This is also because the position at which the displacement sensor 24 measures the oscillating displacement of the oscillating member 23 is on a line that passes through the torsion axis X of the torsion bar 30 and is perpendicular to the torsion axis X.

  As described above, in the seat load detection device 1 of the present invention, the swing of the swinging portion 23b of the swinging member 23 is restricted in the vertical direction by limiting the displacement of the protruding portion 23a of the swinging member 23 to a predetermined amount. When the displacement of the lower arm 11 is appropriately limited and the displacement of the lower arm 11 is limited to a predetermined amount, other movements are also appropriately limited. As a result, it is possible to prevent problems such as deformation of other members such as the lower arm 11 and the base bracket 20 that are directly or indirectly connected to the swing member 23 due to unexpected movement.

<Another embodiment>
<1>
In the above embodiment, the example in which the swing member 23 and the base bracket 20 are bent in the direction away from the lower arm 11 has been described. However, whether or not each of the swing member 23, the base bracket 20 and the lower arm 11 is bent is appropriately determined. It can be changed. Specifically, the position at which the displacement sensor 24 mounted on the swing member 23 measures the swing displacement of the swing member 23 passes through the twist axis X of the torsion bar 30 and is relative to the twist axis X. Therefore, the bent state of the swing member 23, the base bracket 20 and the lower arm 11 can be changed as appropriate.

  For example, FIG. 7 shows another embodiment of the seat load detection device. In this seat load detection device, the lower arm 11 is bent in a direction away from the swinging member 23 and the base bracket 20, so that the displacement sensor 24 attached to the swinging member 23 swings the swinging member 23. The position at which the dynamic displacement is measured can be on a line passing through the torsion axis X of the torsion bar 30 and perpendicular to the torsion axis X.

<2>
In the above embodiment, an example in which the swing element 23 is provided with the hall element portion 25 and the base bracket 20 is provided with the magnet portion 26 has been described. However, the base bracket 20 is provided with the hall element portion 25 and the swing member 23 is provided with a magnet. The portion 26 may be modified to be provided.

<3>
In the above-described embodiment, the example in which the seat load detection devices 1 are provided at a total of four locations below the vehicle seat 10 has been described. However, any number of seat loads may be used as long as the seat load can be detected while the occupant is seated. For example, you may modify | change so that the seat load detection apparatus 1 may be provided in two right and left places of the front side of the vehicle seat 10. FIG.

<4>
In the above embodiment, the structure of the seat load detection device and the mounting structure thereof have been described with reference to the drawings. However, the shape and size of each member can be changed as appropriate. For example, when the projecting portion 23 a of the swing member 23 is inserted into the first hole 21 of the base bracket 20, the gap between them and the swing member 23 in the second hole 33 of the lower arm 11 are inserted. When the connecting portion 23c is inserted, the gap existing between them can be set as appropriate.

The figure which shows the state which attached the seat load detection apparatus to the vehicle seat Side view of seat load detection device Cross section of seat load detector Longitudinal sectional view taken along line BB in FIG. Longitudinal sectional view taken along line CC in FIG. Longitudinal sectional view taken along line DD in FIG. Cross section of another seat load detector (A) is a cross-sectional view of the seat load detection device, (B) is a side view of the seat load detection device.

Explanation of symbols

1 Seat Load Detection Device 11 Lower Arm (Seat Part Side Member)
20 Base bracket (vehicle body side member)
23 oscillating member 24 displacement sensor (load detection means)
30 Torsion bar 30a Oscillating side end 30b Car body side end 31 Connecting part 32 Oscillating force input part X Twist axis X0 Twist center

Claims (3)

A seat load detection device for detecting a seat load acting on a seating portion of a vehicle seat,
A connecting portion for connecting to a seating portion side member fixed to the seating portion side, and a position close to the connecting portion in the horizontal direction, and receives a seat load from the seating portion side member at the connecting portion. A swinging member having a swinging force input unit to which the swinging force generated in the vertical direction is input;
A vehicle body side member fixed to the vehicle body side is fixed to the vehicle body side end portion which is one end side, and the rocking member is fixed to the rocking side end portion which is the other end side, and the rocking force input portion is A torsion bar that twists about a horizontal twist axis when swinging in the vertical direction;
The torsion axis of the swing member relative to the vehicle body side member measured at a position passing through the torsion center of the torsion bar and on a line perpendicular to the torsion axis and away from the torsion axis. A seat load detection device comprising: load detection means for detecting the seat load based on a surrounding displacement. The swinging member and the seating portion side member are sequentially arranged from the vehicle body side member fixed to the vehicle body side end portion of the torsion bar toward the protruding direction of the torsion bar,
The swing member swings in a vertical direction, and projects from the swing unit in the same direction as the projecting direction to connect the swing unit and the swing side end of the torsion bar. With a connecting part,
The seat load detection device according to claim 1, wherein at least one of the swinging member and the seating portion side member is bent in a direction away from each other.   The seat load detection device according to claim 2, wherein the connection portion is inserted in a through hole provided in the seating portion side member with a gap in the vertical direction.

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