EP2477848A1 - Vehicle seat occupancy sensor - Google Patents

Vehicle seat occupancy sensor

Info

Publication number
EP2477848A1
EP2477848A1 EP10763427A EP10763427A EP2477848A1 EP 2477848 A1 EP2477848 A1 EP 2477848A1 EP 10763427 A EP10763427 A EP 10763427A EP 10763427 A EP10763427 A EP 10763427A EP 2477848 A1 EP2477848 A1 EP 2477848A1
Authority
EP
European Patent Office
Prior art keywords
seat
sensor elements
vehicle
seat occupancy
inclination angle
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP10763427A
Other languages
German (de)
French (fr)
Inventor
Hitoshi Yuasa
Hiroyuki Takahashi
Setsu Takuma
Keiichi Yanai
Hideki Kawabata
Wataru Otake
Hiromi Kondo
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Toyota Motor Corp
Aisin Corp
Original Assignee
Aisin Seiki Co Ltd
Toyota Motor Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Aisin Seiki Co Ltd, Toyota Motor Corp filed Critical Aisin Seiki Co Ltd
Publication of EP2477848A1 publication Critical patent/EP2477848A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
    • B60R21/00—Arrangements or fittings on vehicles for protecting or preventing injuries to occupants or pedestrians in case of accidents or other traffic risks
    • B60R21/01—Electrical circuits for triggering passive safety arrangements, e.g. airbags, safety belt tighteners, in case of vehicle accidents or impending vehicle accidents
    • B60R21/015—Electrical circuits for triggering passive safety arrangements, e.g. airbags, safety belt tighteners, in case of vehicle accidents or impending vehicle accidents including means for detecting the presence or position of passengers, passenger seats or child seats, and the related safety parameters therefor, e.g. speed or timing of airbag inflation in relation to occupant position or seat belt use
    • B60R21/01512—Passenger detection systems
    • B60R21/01516—Passenger detection systems using force or pressure sensing means
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60N—SEATS SPECIALLY ADAPTED FOR VEHICLES; VEHICLE PASSENGER ACCOMMODATION NOT OTHERWISE PROVIDED FOR
    • B60N2/00—Seats specially adapted for vehicles; Arrangement or mounting of seats in vehicles
    • B60N2/002—Seats provided with an occupancy detection means mounted therein or thereon
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01G—WEIGHING
    • G01G19/00—Weighing apparatus or methods adapted for special purposes not provided for in the preceding groups
    • G01G19/40—Weighing apparatus or methods adapted for special purposes not provided for in the preceding groups with provisions for indicating, recording, or computing price or other quantities dependent on the weight
    • G01G19/413—Weighing apparatus or methods adapted for special purposes not provided for in the preceding groups with provisions for indicating, recording, or computing price or other quantities dependent on the weight using electromechanical or electronic computing means
    • G01G19/414—Weighing apparatus or methods adapted for special purposes not provided for in the preceding groups with provisions for indicating, recording, or computing price or other quantities dependent on the weight using electromechanical or electronic computing means using electronic computing means only
    • G01G19/4142—Weighing apparatus or methods adapted for special purposes not provided for in the preceding groups with provisions for indicating, recording, or computing price or other quantities dependent on the weight using electromechanical or electronic computing means using electronic computing means only for controlling activation of safety devices, e.g. airbag systems

Definitions

  • the invention relates to a vehicle seat occupancy sensor that is disposed in a seat of a vehicle to detect the occupancy of the seat, that is, detect the sitting of an occupant in the seat.
  • JP-A-2002- 12074 Japanese Patent Application Publication No. 2002-12074
  • the invention provides a vehicle seat occupancy sensor that is simplified in construction and therefore allows a cost reduction.
  • a first aspect of the invention relates to a vehicle seat occupant sensor.
  • This vehicle seat occupancy sensor includes a plurality of sensor elements that are disposed in a seat of a vehicle and that each activate upon receiving a pressure that is greater than or equal to a predetermined value, and at least two of the plurality of sensor elements are arranged so that arrangement of the at least two sensor elements is inclined from a center line of the seat which extends in a longitudinal direction of the seat, to only one of a leftward direction and a rightward direction at an inclination angle within a range of 7° to 16.5° with respect to the center line.
  • the vehicle seat occupancy sensor in accordance with the first aspect of the invention since at least two of the plurality of sensor elements are arranged so that the arrangement thereof is inclined from the longitudinal center line of the seat to only one of a leftward direction and a rightward direction at a predetermined inclination angle, the number of the sensor elements disposed is smaller than in the related art, and it is easier to dispose the sensor elements than in the related art. Therefore, the vehicle seat occupancy sensor in accordance with the first aspect is able to realize simplification of construction and achieve reduction of cost. Besides, since the inclination angle is within the range of 7° to 16.5°, the vehicle seat occupancy sensor is able to detect the seat occupant by a child, that is, the sitting of a child in the seat, as well as the seat occupancy by an adult.
  • the plurality of sensor elements may be disposed only in a half region of the seat that is on a left side and a right side of a center of the seat. Due to this, the number of sensor elements is less than in the related art, and it is easier to dispose the sensor elements than in the related art. Hence, it is possible to realize simplification of construction and achieve reduction of cost.
  • an arrangement pitch of the plurality of sensor elements in the longitudinal direction of the vehicle may be within a range of 30 mm to 50 mm. Due to this, false detection caused by a piece of luggage can be prevented.
  • the inclination angle may be within a range of to 15°. Due to this, it is possible to detect the seat occupancy by a child as well as the seat occupancy by an adult.
  • a second aspect of the invention relates to a vehicle seat occupancy sensor.
  • This vehicle seat occupancy sensor includes a plurality of sensor elements that are disposed in a seat of a vehicle and that each activate upon receiving a pressure that is greater than or equal to a predetermined value, and the plurality of sensor elements are arranged so that arrangement of the plurality of sensor elements is inclined from a center line of the seat which extends in a longitudinal direction of the seat, to only one of a leftward direction and a rightward direction at a predetermined inclination angle, and the inclination angle is less than or equal to 16.5°.
  • the vehicle seat occupancy sensor in accordance with the second aspect of the invention, since the plurality of sensor elements are arranged so that the arrangement thereof is inclined from the longitudinal center line of the seat to only one of a leftward direction and a rightward direction at a predetermined inclination angle, the number of the sensor elements disposed is smaller than in the related art, and it is easier to dispose the sensor elements than in the related art. Therefore, the vehicle seat occupancy sensor is able to realize simplification of construction and achieve reduction of cost. Besides, since the inclination angle is less than or equal to 16.5°, it is possible to detect the seat occupancy by a child, that is, the sitting of a child in the seat, as well as the seat occupancy by an adult.
  • the inclination angle may be less than or equal to 15°. Due to this, it is possible to accurately detect the seat occupancy by a child as well as the seat occupancy by an adult.
  • a third aspect of the invention relates to a vehicle seat occupancy sensor.
  • This vehicle seat occupancy sensor includes a plurality of sensor elements that are disposed in a seat of a vehicle and that each activate upon receiving a pressure that is greater than or equal to a predetermined value, and the plurality of sensor elements are arranged so that arrangement of the plurality of sensor elements is inclined from a center line of the seat which extends in a longitudinal direction of the seat, to only one of a leftward direction and a rightward direction at a predetermined inclination angle with respect to the center line, and the inclination angle is greater than or equal to 7°.
  • the vehicle seat occupancy sensor in accordance with the third aspect of the invention, since the plurality of sensor elements are arranged so that the arrangement thereof is inclined from the longitudinal center line of the seat to only one of a leftward direction and a rightward direction at a predetermined inclination angle, the number of the sensor elements disposed is smaller than in the related art, and it is easier to dispose the sensor elements than in the related art. Therefore, the vehicle seat occupancy sensor is able to realize simplification of construction and achieve reduction of cost. Besides, since the inclination angle is greater than or equal to 7°, it is possible to prevent a child's "crotch escape" from detection.
  • crotch escape refers to a phenomenon in which since a region of a human body between the left and right hipbones does not easily give load to the seat, the load at a site that corresponds to the crotch cannot be detected by a sensor.
  • a fourth aspect of the invention relates to a vehicle seat occupancy sensor.
  • This vehicle seat occupancy sensor includes a plurality of sensor elements that are disposed in a seat of a vehicle and that each activate upon receiving a pressure that is greater than or equal to a predetermined value, and the plurality of sensor elements are provided only in a whole or a portion of a range of angle of 7° to 16.5° with respect to a center line of the seat that extends in a longitudinal direction of the seat.
  • the vehicle seat occupancy sensor in accordance with the fourth aspect of the invention since the plurality of sensor elements are provided in the whole or a portion of the range of 7° to 16.5° with respect to the longitudinal center line of the seat, the number of the sensor elements disposed is smaller than in the related art, and it is easier to dispose the sensor elements than in the related art. Therefore, it is possible to realize simplification of construction and achieve reduction of cost. Besides, since the inclination angle is in the range of 7° to 16.5°, it is possible to detect the seat occupancy by a child as well as the seat occupancy by an adult.
  • FIG 1 is a plan view of a vehicle seat occupancy sensor in accordance with an embodiment of the invention
  • FIG 2A is a diagram showing distributions of the sitting pressure occurring in a seat cushion when an adult properly sits and when a six-year-old child properly sits
  • FIG 2B is a diagram showing distributions of the sitting pressure occurring in the seat cushion when the adult sits back in the seat and when the six-year-old child sits back in the seat
  • FIG 2C is a diagram showing distributions of the sitting pressure occurring in the seat cushion when the adult sits one-sided and when the six-year-old child sits one-sided;
  • FIG 3 is a plan view showing positions at which vehicle seat occupancy sensor elements are disposed
  • FIG 4 is a diagram showing the sensor installation angle and the probability of detection.
  • FIG 5 is a diagram showing ranges where sensor elements are installed.
  • FIG 1 is a plan view showing a vehicle seat occupancy sensor in accordance with an embodiment of the invention.
  • a vehicle seat occupancy sensor 10 in accordance with this embodiment is disposed in a seat cushion 12 of a vehicle seat 18.
  • the seat cushion 12 is formed so as to have a recess shape that conforms to a hip shape of occupants.
  • the vehicle seat occupancy sensor 10 has a four pressure sensitive sensor elements 14 (i.e., a first pressure sensitive sensor element 14a, a second pressure sensitive sensor element 14b, a third pressure sensitive sensor element 14c, and a fourth pressure sensitive sensor element 14d).
  • the pressure sensitive sensor elements 14 are arranged only in one side portion of the seat cushion 12, and are embedded within the seat cushion 12.
  • Each of these pressure sensitive sensor elements 14 activates when a pressure that is greater than or equal to a predetermined value acts thereon.
  • Examples of the pressure sensitive sensor elements 14 include sensors that turn on when the pressure becomes equal to or greater than a threshold value through the use of a button switch, a pressurized electroconductive rubber, etc. Then, the four pressure sensitive sensor elements 14 are linked to a connector 16 that is provided at the rear of the seat cushion 12 and on a center axis of the seat cushion 12. Via the connector 16, the pressure sensitive sensor elements 14 are connected to a seat occupancy determination ECU (Electronic Control Unit) (not shown).
  • the pressure sensitive sensor elements used herein may be, for example, sensors whose electric resistance changes according to the stress and sensors whose capacitance changes according to the stress as well as other types of sensors.
  • the four pressure sensitive sensor elements 14 are disposed asymmetrically about a longitudinal center line LI of the seat 18. Concretely, as shown in FIG. 1, the four pressure sensitive sensor elements 14 are linearly arranged. The linear arrangement of the pressure sensitive sensor elements 14 is inclined only to the right from the center line LI. That is, the four pressure sensitive sensor elements 14 are arranged from a rear central portion of the seat cushion 12 toward a front of the vehicle with an inclination to the right side. Then, an inclination angle a between a straight line L2 along the linear arrangement of the four pressure sensitive sensor elements 14 and the center line LI of the seat cushion 12 is preferably in the range of 7° to 16.5°, and more preferably in the range of 7° to 15°.
  • the straight line L2 extends in a direction from a widthwise center of a sitting surface for one person on the seat 18 toward an outer side of the vehicle and toward a front of the vehicle, and is inclined at an angle of 7° with respect to the center line LI that extends in the longitudinal direction of the seat 18.
  • the straight line L2 is preferably a line that passes through a site that is located 85 mm to 110 mm rearward from a hip point.
  • the hip point herein is a position that represents a hip joint point of a person seated in the seat 18. The hip point can be measured by using a common three-dimensional mannequin.
  • FIGS. 2A to 2C show results of examination about the sitting pressures of adults and children through the use of the pressure sensitive sensor elements 14.
  • a region A denotes a sitting-pressure-on region of an adult
  • a region B denotes a sitting-pressure-on region of a six-year-old child.
  • a point PI denotes a 3DM hip point (hereinafter, abbreviated as H.P.)
  • a point P2 denotes a six-year-old child's H.P.
  • a point P3 denotes an adult's H.P.
  • the hip point refers to a point that corresponds to a center of rotation of the trunk and the thighs of a three-dimensional dummy for measurement of internal dimensions of motor vehicle cabins according to D4607-1977 of JIS (Japan Industrial Standards).
  • FIG 2A shows the sitting pressure distributions occurring when an adult properly sits and when a six-year-old child properly sits.
  • the point PI, the point P2 and the point P3, respectively are located substantially linearly in the longitudinal direction of the vehicle, and the six-year-old child's sitting-pressure-on region B. is within the adult's sitting-pressure-on region A.
  • FIG- 2B shows the sitting pressure distributions occurring when the adult sits back and when the six-year-old child sits back.
  • the point PI of the dummy and the point P2 of the six-year-old child are located substantially linearly in the longitudinal direction of the vehicle, and the sitting-pressure-on region B of the six-year-old child is within the sitting-pressure-on region A of the adult.
  • FIG 2C shows the sitting pressure distributions occurring when the adult sits one-sided, that is, sits with a deviation to a side, and when the six-year-old child sits one-sided.
  • the point PI of the dummy, the point P2 of the six-year-old child and the point P3 of the adult are located substantially linearly in the transverse direction of the vehicle.
  • the adult's sitting-pressure-on region A is more external than the six-year-old child's sitting-pressure-on region B since the adult's hip is larger than the six-year-old child's hip. Therefore, as long as the seat occupancy by a six-year-old child, that is, the sitting of a six-year-old child in the seat, can be detected, the seat occupancy by an adult can also be detected.
  • the detection region is determined by a detection region for six-year-old children.
  • FIG ' 3 is a plan view showing the positions at which vehicle seat occupancy sensor elements are disposed.
  • the forward located first and second cells SI and S2 correspond to the sitting forward of six-year-old children
  • the rearward located third and fourth cells S3 and S4 correspond to the sitting back of six-year-old children.
  • the first pressure sensitive sensor element 14a, the second pressure sensitive sensor element 14b, the third pressure sensitive sensor element 14c, and the fourth pressure sensitive sensor element 14d are disposed at positions where at least two of the first to fourth cells SI to S4 overlap with each other.
  • the four pressure sensitive sensor elements 14 are disposed only in a substantially half portion of the seat 18 that is in the left or right side of the center of the seat 18 (the right side of the center in this embodiment). Concretely, the four pressure sensitive sensor elements 14 are disposed only to the right of the center line LI of the seat cushion 12, and are inclined at a predetermined inclination angle a with respect to the center line LI. The pressure sensitive sensor elements 14 are disposed only in an inclined region, and not disposed in the other regions.
  • the pitch between the pressure sensitive sensor elements 14 in the longitudinal direction of the vehicle is set at 30 mm to 50 mm.
  • the four pressure sensitive sensor elements 14 are disposed obliquely.
  • the inclination angle a between the center line LI of the seat 18 and the straight line L2 along the linear arrangement of the four pressure sensitive sensor elements 14 is set within the range of 7° to 16.5°.
  • the inclination angle a between the center line LI and the straight line L2 along the arrangement of the pressure sensitive sensor elements 14 be within the range of 7° to 16.5°.
  • the inclination angle a is preferred to be within the range of 7° to 15°.
  • the position of the arrangement of the pressure sensitive sensor elements 14 does not have any particular preference in direction, that is, as to whether the pressure sensitive sensor elements 14 are preferred to be disposed in the seat at an inner side or an outer side with respect to the vehicle.
  • a rear seat occupants often sit looking in the direction of a center of the front seat row or a center of the windshield, and therefore often sit center-sided, that is, closer to the center of the vehicle. Therefore, in the case where the seat in question is a rear seat, it is preferable that the pressure sensitive sensor elements 14 be disposed closer to the center of the vehicle.
  • FIG 4 is a diagram showing the sensor installation angle and the probability of detection.
  • the horizontal axis represents the sensor installation angle
  • the vertical axis represents the probability of detection.
  • FIG 5 shows regions where sensors are disposed as results of an examination performed about the sitting-pressure-on region of six-year-old children.
  • load does not act in a portion that corresponds to the crotch of a six-year-old child, the "crotch escape from detection" is likely to occur.
  • the lower limit value of the inclination angle a is set at 7°.
  • the four pressure sensitive sensor elements 14 are arranged on a straight line segment that starts from the center line LI and extends only in a rightward direction at an inclination angle a with respect to the center line LI, so that the number of pressure sensitive sensor elements 14 disposed is smaller than the number thereof in the related art, and it suffices to dispose the pressure sensitive sensor elements 14 linearly.
  • the inclination angle is within the range of 7° to 16.5°, it is possible to detect the seat occupancy by a child as well as the seat occupancy by an adult.
  • simplification may be achieved by avoiding provision of a sensor outside the range of angle of 7° to 16.5°.
  • the foregoing embodiment illustrates an example of a vehicle seat occupancy sensor in accordance with the invention.
  • the vehicle seat occupancy sensor in accordance with the invention is not limited to those described above in conjunction with the foregoing embodiments.
  • the vehicle seat occupancy sensor in accordance with the invention may also be a vehicle seat occupancy sensor that is modified from any one of the vehicle seat occupancy sensors of the embodiments without departing from the gist described in the appended claims for patent, or that is applied to a construction that is different from what is described above.
  • the four pressure sensitive sensor elements 14 are linearly arranged, this arrangement is not restrictive, that is, the arrangement does not need to be perfectly linear.
  • the four pressure sensitive sensor elements 14 are disposed inclined only in a rightward direction with respect to the center line LI, the pressure sensitive sensor elements 14 may also be disposed inclined only in a leftward direction with respect to the center line LI, or may also be disposed inclined in both leftward and rightward directions with respect to the center line LI.
  • the pressure sensitive sensor elements 14 may be disposed in a region in the seat cushion 12 that is on an inner side of a straight line that connects a point located within a region that corresponds to the adult's hipbones and a site that corresponds to a center of a rear end of the adult's hipbones in the seat cushion 12.
  • the number of pressure sensitive sensor elements 14 disposed is less than in the related art, and it is easier to dispose the pressure sensitive sensor elements 14 than in the related art. Therefore, simplification of construction can be realized, and reduction of cost can be achieved.
  • the foregoing sensor arrangement makes it possible to detect the seat occupancy by a child as well as the seat occupancy by an adult.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Mathematical Physics (AREA)
  • Theoretical Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Physics & Mathematics (AREA)
  • Aviation & Aerospace Engineering (AREA)
  • Transportation (AREA)
  • Seats For Vehicles (AREA)

Abstract

A vehicle seat occupancy sensor (10) disposed in a vehicle seat (18) includes a plurality of sensor elements (14) that each activate upon receiving a pressure of a predetermined value or greater. At least two of the sensor elements (14a, 14b) are arranged along a line (L1) that is inclined from a center line of the seat which extends in a longitudinal direction of the seat, to only one of a leftward direction and a rightward direction at an inclination angle within a range of 7° to 16.5°.

Description

VEHICLE SEAT OCCUPANCY SENSOR
BACKGROUND OF THE INVENTION
1. Field of the Invention
[0001] The invention relates to a vehicle seat occupancy sensor that is disposed in a seat of a vehicle to detect the occupancy of the seat, that is, detect the sitting of an occupant in the seat.
2. Description of the Related Art
[0002] In a known vehicle seat occupancy sensor, sensor elements are arranged in a grid pattern, covering the entire sitting surface of a seat, as described in, for example, Japanese Patent Application Publication No. 2002-12074 (JP-A-2002- 12074). According to this construction, when an occupant sits on the sitting surface of the seat, a grid-pattern sensor is able to accurately detect the load of the occupant in a planar fashion.
[0003] However, in the foregoing seat occupancy sensor, since many sensor elements are used, the arrangement of the sensor elements, the wiring construction for linking the sensor elements, etc., are complicated. Therefore, the construction of the seat occupancy sensor is difficult to simplify, which gives rise to a problem of high cost.
SUMMARY OF THE INVENTION
[0004] . The invention provides a vehicle seat occupancy sensor that is simplified in construction and therefore allows a cost reduction.
[0005] A first aspect of the invention relates to a vehicle seat occupant sensor. This vehicle seat occupancy sensor includes a plurality of sensor elements that are disposed in a seat of a vehicle and that each activate upon receiving a pressure that is greater than or equal to a predetermined value, and at least two of the plurality of sensor elements are arranged so that arrangement of the at least two sensor elements is inclined from a center line of the seat which extends in a longitudinal direction of the seat, to only one of a leftward direction and a rightward direction at an inclination angle within a range of 7° to 16.5° with respect to the center line.
[0006] In the vehicle seat occupancy sensor in accordance with the first aspect of the invention, since at least two of the plurality of sensor elements are arranged so that the arrangement thereof is inclined from the longitudinal center line of the seat to only one of a leftward direction and a rightward direction at a predetermined inclination angle, the number of the sensor elements disposed is smaller than in the related art, and it is easier to dispose the sensor elements than in the related art. Therefore, the vehicle seat occupancy sensor in accordance with the first aspect is able to realize simplification of construction and achieve reduction of cost. Besides, since the inclination angle is within the range of 7° to 16.5°, the vehicle seat occupancy sensor is able to detect the seat occupant by a child, that is, the sitting of a child in the seat, as well as the seat occupancy by an adult.
[0007] In the foregoing construction of the first aspect of the invention, the plurality of sensor elements may be disposed only in a half region of the seat that is on a left side and a right side of a center of the seat. Due to this, the number of sensor elements is less than in the related art, and it is easier to dispose the sensor elements than in the related art. Hence, it is possible to realize simplification of construction and achieve reduction of cost.
[0008] In the forgoing construction, an arrangement pitch of the plurality of sensor elements in the longitudinal direction of the vehicle may be within a range of 30 mm to 50 mm. Due to this, false detection caused by a piece of luggage can be prevented.
[0009] In the foregoing construction, the inclination angle may be within a range of to 15°. Due to this, it is possible to detect the seat occupancy by a child as well as the seat occupancy by an adult.
[0010] A second aspect of the invention relates to a vehicle seat occupancy sensor. This vehicle seat occupancy sensor includes a plurality of sensor elements that are disposed in a seat of a vehicle and that each activate upon receiving a pressure that is greater than or equal to a predetermined value, and the plurality of sensor elements are arranged so that arrangement of the plurality of sensor elements is inclined from a center line of the seat which extends in a longitudinal direction of the seat, to only one of a leftward direction and a rightward direction at a predetermined inclination angle, and the inclination angle is less than or equal to 16.5°.
[0011] In the vehicle seat occupancy sensor in accordance with the second aspect of the invention, since the plurality of sensor elements are arranged so that the arrangement thereof is inclined from the longitudinal center line of the seat to only one of a leftward direction and a rightward direction at a predetermined inclination angle, the number of the sensor elements disposed is smaller than in the related art, and it is easier to dispose the sensor elements than in the related art. Therefore, the vehicle seat occupancy sensor is able to realize simplification of construction and achieve reduction of cost. Besides, since the inclination angle is less than or equal to 16.5°, it is possible to detect the seat occupancy by a child, that is, the sitting of a child in the seat, as well as the seat occupancy by an adult.
[0012] In the foregoing construction, the inclination angle may be less than or equal to 15°. Due to this, it is possible to accurately detect the seat occupancy by a child as well as the seat occupancy by an adult.
[0013] A third aspect of the invention relates to a vehicle seat occupancy sensor. This vehicle seat occupancy sensor includes a plurality of sensor elements that are disposed in a seat of a vehicle and that each activate upon receiving a pressure that is greater than or equal to a predetermined value, and the plurality of sensor elements are arranged so that arrangement of the plurality of sensor elements is inclined from a center line of the seat which extends in a longitudinal direction of the seat, to only one of a leftward direction and a rightward direction at a predetermined inclination angle with respect to the center line, and the inclination angle is greater than or equal to 7°.
[0014] In the vehicle seat occupancy sensor in accordance with the third aspect of the invention, since the plurality of sensor elements are arranged so that the arrangement thereof is inclined from the longitudinal center line of the seat to only one of a leftward direction and a rightward direction at a predetermined inclination angle, the number of the sensor elements disposed is smaller than in the related art, and it is easier to dispose the sensor elements than in the related art. Therefore, the vehicle seat occupancy sensor is able to realize simplification of construction and achieve reduction of cost. Besides, since the inclination angle is greater than or equal to 7°, it is possible to prevent a child's "crotch escape" from detection. The term crotch escape herein refers to a phenomenon in which since a region of a human body between the left and right hipbones does not easily give load to the seat, the load at a site that corresponds to the crotch cannot be detected by a sensor.
[0015] A fourth aspect of the invention relates to a vehicle seat occupancy sensor. This vehicle seat occupancy sensor includes a plurality of sensor elements that are disposed in a seat of a vehicle and that each activate upon receiving a pressure that is greater than or equal to a predetermined value, and the plurality of sensor elements are provided only in a whole or a portion of a range of angle of 7° to 16.5° with respect to a center line of the seat that extends in a longitudinal direction of the seat.
[0016] In the vehicle seat occupancy sensor in accordance with the fourth aspect of the invention, since the plurality of sensor elements are provided in the whole or a portion of the range of 7° to 16.5° with respect to the longitudinal center line of the seat, the number of the sensor elements disposed is smaller than in the related art, and it is easier to dispose the sensor elements than in the related art. Therefore, it is possible to realize simplification of construction and achieve reduction of cost. Besides, since the inclination angle is in the range of 7° to 16.5°, it is possible to detect the seat occupancy by a child as well as the seat occupancy by an adult.
[0017] According to the invention, it is possible to provide a vehicle seat occupancy sensor that allows simplification of construction and reduction of cost.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The features, advantages, and technical and industrial significance of this invention will be described below with reference to the accompanying drawings, in which like numerals denote like elements, and wherein: FIG 1 is a plan view of a vehicle seat occupancy sensor in accordance with an embodiment of the invention;
FIG 2A is a diagram showing distributions of the sitting pressure occurring in a seat cushion when an adult properly sits and when a six-year-old child properly sits, and FIG 2B is a diagram showing distributions of the sitting pressure occurring in the seat cushion when the adult sits back in the seat and when the six-year-old child sits back in the seat, and FIG 2C is a diagram showing distributions of the sitting pressure occurring in the seat cushion when the adult sits one-sided and when the six-year-old child sits one-sided;
FIG 3 is a plan view showing positions at which vehicle seat occupancy sensor elements are disposed;
FIG 4 is a diagram showing the sensor installation angle and the probability of detection; and
FIG 5 is a diagram showing ranges where sensor elements are installed.
DETAILED DESCRIPTION OF EMBODIMENTS
[0019] Embodiments of the invention will be described with reference to the accompanying drawings. FIG 1 is a plan view showing a vehicle seat occupancy sensor in accordance with an embodiment of the invention. A vehicle seat occupancy sensor 10 in accordance with this embodiment is disposed in a seat cushion 12 of a vehicle seat 18. The seat cushion 12 is formed so as to have a recess shape that conforms to a hip shape of occupants.
[0020] The vehicle seat occupancy sensor 10 has a four pressure sensitive sensor elements 14 (i.e., a first pressure sensitive sensor element 14a, a second pressure sensitive sensor element 14b, a third pressure sensitive sensor element 14c, and a fourth pressure sensitive sensor element 14d). The pressure sensitive sensor elements 14 are arranged only in one side portion of the seat cushion 12, and are embedded within the seat cushion 12.
[0021] Each of these pressure sensitive sensor elements 14 activates when a pressure that is greater than or equal to a predetermined value acts thereon. Examples of the pressure sensitive sensor elements 14 include sensors that turn on when the pressure becomes equal to or greater than a threshold value through the use of a button switch, a pressurized electroconductive rubber, etc. Then, the four pressure sensitive sensor elements 14 are linked to a connector 16 that is provided at the rear of the seat cushion 12 and on a center axis of the seat cushion 12. Via the connector 16, the pressure sensitive sensor elements 14 are connected to a seat occupancy determination ECU (Electronic Control Unit) (not shown). The pressure sensitive sensor elements used herein may be, for example, sensors whose electric resistance changes according to the stress and sensors whose capacitance changes according to the stress as well as other types of sensors.
[0022] The four pressure sensitive sensor elements 14 are disposed asymmetrically about a longitudinal center line LI of the seat 18. Concretely, as shown in FIG. 1, the four pressure sensitive sensor elements 14 are linearly arranged. The linear arrangement of the pressure sensitive sensor elements 14 is inclined only to the right from the center line LI. That is, the four pressure sensitive sensor elements 14 are arranged from a rear central portion of the seat cushion 12 toward a front of the vehicle with an inclination to the right side. Then, an inclination angle a between a straight line L2 along the linear arrangement of the four pressure sensitive sensor elements 14 and the center line LI of the seat cushion 12 is preferably in the range of 7° to 16.5°, and more preferably in the range of 7° to 15°.
[0023] Incidentally, as for the direction of the inclination in this example, the straight line L2 extends in a direction from a widthwise center of a sitting surface for one person on the seat 18 toward an outer side of the vehicle and toward a front of the vehicle, and is inclined at an angle of 7° with respect to the center line LI that extends in the longitudinal direction of the seat 18. Besides, the straight line L2 is preferably a line that passes through a site that is located 85 mm to 110 mm rearward from a hip point. The hip point herein is a position that represents a hip joint point of a person seated in the seat 18. The hip point can be measured by using a common three-dimensional mannequin.
[0024] Reasons why the four pressure sensitive sensor elements 14 are disposed only in one side portion of the seat cushion 12. FIGS. 2A to 2C show results of examination about the sitting pressures of adults and children through the use of the pressure sensitive sensor elements 14. In FIGS. 2A to 2C, a region A denotes a sitting-pressure-on region of an adult, and a region B denotes a sitting-pressure-on region of a six-year-old child. Besides, a point PI denotes a 3DM hip point (hereinafter, abbreviated as H.P.), and a point P2 denotes a six-year-old child's H.P., and a point P3 denotes an adult's H.P. Incidentally, the hip point refers to a point that corresponds to a center of rotation of the trunk and the thighs of a three-dimensional dummy for measurement of internal dimensions of motor vehicle cabins according to D4607-1977 of JIS (Japan Industrial Standards).
[0025] FIG 2A shows the sitting pressure distributions occurring when an adult properly sits and when a six-year-old child properly sits. As shown in FIG. 2A, in the cases where the dummy, the six-year-old child or the adult properly sits, the point PI, the point P2 and the point P3, respectively, are located substantially linearly in the longitudinal direction of the vehicle, and the six-year-old child's sitting-pressure-on region B. is within the adult's sitting-pressure-on region A.
[00261 FIG- 2B shows the sitting pressure distributions occurring when the adult sits back and when the six-year-old child sits back. As shown in FIG 2B, in the cases of sitting back, the point PI of the dummy and the point P2 of the six-year-old child are located substantially linearly in the longitudinal direction of the vehicle, and the sitting-pressure-on region B of the six-year-old child is within the sitting-pressure-on region A of the adult.
[0027] FIG 2C shows the sitting pressure distributions occurring when the adult sits one-sided, that is, sits with a deviation to a side, and when the six-year-old child sits one-sided. As shown in FIG 2C, in the cases of sitting one-sided, the point PI of the dummy, the point P2 of the six-year-old child and the point P3 of the adult are located substantially linearly in the transverse direction of the vehicle.
[0028] From the foregoing results of examination about the situations of sitting pressure of occupants, the adult's sitting-pressure-on region A is more external than the six-year-old child's sitting-pressure-on region B since the adult's hip is larger than the six-year-old child's hip. Therefore, as long as the seat occupancy by a six-year-old child, that is, the sitting of a six-year-old child in the seat, can be detected, the seat occupancy by an adult can also be detected. In view of this respect, the detection region is determined by a detection region for six-year-old children.
[0029] FIG ' 3 is a plan view showing the positions at which vehicle seat occupancy sensor elements are disposed. In FIG 3, the forward located first and second cells SI and S2 correspond to the sitting forward of six-year-old children, and the rearward located third and fourth cells S3 and S4 correspond to the sitting back of six-year-old children. The first pressure sensitive sensor element 14a, the second pressure sensitive sensor element 14b, the third pressure sensitive sensor element 14c, and the fourth pressure sensitive sensor element 14d are disposed at positions where at least two of the first to fourth cells SI to S4 overlap with each other.
[0030] The four pressure sensitive sensor elements 14 are disposed only in a substantially half portion of the seat 18 that is in the left or right side of the center of the seat 18 (the right side of the center in this embodiment). Concretely, the four pressure sensitive sensor elements 14 are disposed only to the right of the center line LI of the seat cushion 12, and are inclined at a predetermined inclination angle a with respect to the center line LI. The pressure sensitive sensor elements 14 are disposed only in an inclined region, and not disposed in the other regions.
[0031] In order to prevent a false detection of seat occupancy caused by a piece of luggage, the pitch between the pressure sensitive sensor elements 14 in the longitudinal direction of the vehicle is set at 30 mm to 50 mm. In order to prevent a child's "crotch escape" from detection, the four pressure sensitive sensor elements 14 are disposed obliquely. The inclination angle a between the center line LI of the seat 18 and the straight line L2 along the linear arrangement of the four pressure sensitive sensor elements 14 is set within the range of 7° to 16.5°.
[0032] In order to detect the occupancy of the seat by a person, including the seat occupancy by a six-year-old child, it is preferable that the inclination angle a between the center line LI and the straight line L2 along the arrangement of the pressure sensitive sensor elements 14 be within the range of 7° to 16.5°. On the other hand, in order to accurately detect the seat occupancy by an adult and by a child, the inclination angle a is preferred to be within the range of 7° to 15°.
[0033] Besides, in the case where the seat in question is a navigator's seat, the position of the arrangement of the pressure sensitive sensor elements 14 does not have any particular preference in direction, that is, as to whether the pressure sensitive sensor elements 14 are preferred to be disposed in the seat at an inner side or an outer side with respect to the vehicle. However, in the case of a rear seat, occupants often sit looking in the direction of a center of the front seat row or a center of the windshield, and therefore often sit center-sided, that is, closer to the center of the vehicle. Therefore, in the case where the seat in question is a rear seat, it is preferable that the pressure sensitive sensor elements 14 be disposed closer to the center of the vehicle.
[0034] Hereinafter, a ground for setting the inclination angle a at 7° to 16.5° will be described with reference to FIGS. 4 and. 5. FIG 4 is a diagram showing the sensor installation angle and the probability of detection. In FIG 4, the horizontal axis represents the sensor installation angle, and the vertical axis represents the probability of detection. As shown in FIG 4, since the sitting position of a six-year-old child is likely to deviate to a side, the detection probability declines if the sensor arrangement is inclined greatly. Taking this into account, the upper limit value of the inclination angle a is set at 16.5° with reference to the graph shown in FIG 4.
[0035] FIG 5 shows regions where sensors are disposed as results of an examination performed about the sitting-pressure-on region of six-year-old children. As shown in FIG 5, since load does not act in a portion that corresponds to the crotch of a six-year-old child, the "crotch escape from detection" is likely to occur.- In order to prevent the six-year-old child's crotch escape from detection, the lower limit value of the inclination angle a is set at 7°.
[0036]' In the vehicle seat occupancy sensor 1 constructed as described above, the four pressure sensitive sensor elements 14 are arranged on a straight line segment that starts from the center line LI and extends only in a rightward direction at an inclination angle a with respect to the center line LI, so that the number of pressure sensitive sensor elements 14 disposed is smaller than the number thereof in the related art, and it suffices to dispose the pressure sensitive sensor elements 14 linearly. Thus, in the embodiment, it is easy to dispose the pressure sensitive sensor elements 14. Therefore, simplification of construction can be realized, and reduction of cost may be achieved. Besides, since the inclination angle is within the range of 7° to 16.5°, it is possible to detect the seat occupancy by a child as well as the seat occupancy by an adult. Besides, simplification may be achieved by avoiding provision of a sensor outside the range of angle of 7° to 16.5°.
[0037] The foregoing embodiment illustrates an example of a vehicle seat occupancy sensor in accordance with the invention. The vehicle seat occupancy sensor in accordance with the invention is not limited to those described above in conjunction with the foregoing embodiments. The vehicle seat occupancy sensor in accordance with the invention may also be a vehicle seat occupancy sensor that is modified from any one of the vehicle seat occupancy sensors of the embodiments without departing from the gist described in the appended claims for patent, or that is applied to a construction that is different from what is described above. For example, although in the foregoing embodiments, the four pressure sensitive sensor elements 14 are linearly arranged, this arrangement is not restrictive, that is, the arrangement does not need to be perfectly linear. Besides, although in the foregoing embodiments, the four pressure sensitive sensor elements 14 are disposed inclined only in a rightward direction with respect to the center line LI, the pressure sensitive sensor elements 14 may also be disposed inclined only in a leftward direction with respect to the center line LI, or may also be disposed inclined in both leftward and rightward directions with respect to the center line LI.
[0038] For example, the pressure sensitive sensor elements 14 may be disposed in a region in the seat cushion 12 that is on an inner side of a straight line that connects a point located within a region that corresponds to the adult's hipbones and a site that corresponds to a center of a rear end of the adult's hipbones in the seat cushion 12. In this case, the number of pressure sensitive sensor elements 14 disposed is less than in the related art, and it is easier to dispose the pressure sensitive sensor elements 14 than in the related art. Therefore, simplification of construction can be realized, and reduction of cost can be achieved. Besides, the foregoing sensor arrangement makes it possible to detect the seat occupancy by a child as well as the seat occupancy by an adult.

Claims

CLAIMS:
1. A vehicle seat occupancy sensor characterized by comprising:
a plurality of sensor elements that are disposed in a seat of a vehicle and that each activate upon receiving a pressure that is greater than or equal to a predetermined value, wherein
at least two of the plurality of sensor elements are arranged so that arrangement of the at least two sensor elements is inclined from a center line of the seat which extends in a longitudinal direction of the seat, to only one of a leftward direction and a rightward direction at an inclination angle within a range of 7° to 16.5° with respect to the center line.
2. The vehicle seat occupancy sensor according to claim 1, wherein the plurality of sensor elements are disposed only in a half region of the seat that is on a left side and a right side of a center of the seat.
3. The vehicle seat occupancy sensor according to claim 1 or 2, wherein an arrangement pitch of the plurality of sensor elements in the longitudinal direction of the vehicle is within a range of 30 mm to 50 mm.
4. The vehicle seat occupancy sensor according to any one of claims 1 to 3, wherein the inclination angle is within a range of 7° to 15°.
5. A vehicle seat occupancy sensor characterized by comprising:
a plurality of sensor elements that are disposed in a seat of a vehicle and that each activate upon receiving a pressure that is greater than or equal to a predetennined value, wherein:
the plurality of sensor elements are arranged so that arrangement of the plurality of sensor elements is inclined from a center line of the seat which extends in a longitudinal direction of the seat, to only one of a leftward direction and a rightward direction at a predetermined inclination angle; and
the predetermined inclination angle is less than or equal to 16.5°.
6. The vehicle seat occupancy sensor according to claim 5, wherein the inclination angle is less than or equal to 15°.
7. A vehicle seat occupancy sensor characterized by comprising:
a plurality of sensor elements that are disposed in a seat of a vehicle and that each activate upon receiving a pressure that is greater than or equal to a predetermined value, wherein:
the plurality of sensor elements are arranged so that arrangement of the plurality of sensor elements is inclined from a center line of the seat which extends in a longitudinal direction of the seat, to only one of a leftward direction and a rightward direction at a predetermined inclination angle with respect to the center line; and
the predetermined inclination angle is greater than or equal to 7°.
8. A vehicle seat occupancy sensor characterized by comprising:
a plurality of sensor elements that are disposed in a seat of a vehicle and that each activate upon receiving a pressure that is greater than or equal to a predetermined value, wherein
the plurality of sensor elements are provided only in a whole or a portion of a range of angle of 7° to 16.5° with respect to a center line of the seat that extends in a longitudinal direction of the seat.
EP10763427A 2009-09-15 2010-09-14 Vehicle seat occupancy sensor Withdrawn EP2477848A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2009213804A JP2011063076A (en) 2009-09-15 2009-09-15 Seating sensor for vehicle
PCT/IB2010/002288 WO2011033360A1 (en) 2009-09-15 2010-09-14 Vehicle seat occupancy sensor

Publications (1)

Publication Number Publication Date
EP2477848A1 true EP2477848A1 (en) 2012-07-25

Family

ID=43304196

Family Applications (1)

Application Number Title Priority Date Filing Date
EP10763427A Withdrawn EP2477848A1 (en) 2009-09-15 2010-09-14 Vehicle seat occupancy sensor

Country Status (4)

Country Link
EP (1) EP2477848A1 (en)
JP (1) JP2011063076A (en)
CN (1) CN102498018A (en)
WO (1) WO2011033360A1 (en)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103264675A (en) * 2013-05-23 2013-08-28 廊坊市金色时光科技发展有限公司 Automobile seat cushion
RS20140183A1 (en) 2014-04-14 2015-10-30 Novelic D.O.O. Radar sensor for detection of seat occupancy that operates in the millimeter wave frequency range and operational method thereof
LU92541B1 (en) * 2014-09-10 2016-03-11 Iee Sarl Radar sensing of vehicle occupancy
LU92651B1 (en) * 2014-12-23 2016-08-10 Iee Sarl SEAT ASSIGNMENT SENSOR UNIT AND SEAT
CN107097699A (en) * 2017-05-18 2017-08-29 上海安闻汽车电子有限公司 A kind of automotive seat
JP7022274B2 (en) * 2017-10-06 2022-02-18 テイ・エス テック株式会社 Seating sensor

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3707363B2 (en) * 2000-06-28 2005-10-19 株式会社デンソー Vehicle seat sensor
US6735508B2 (en) * 2000-07-12 2004-05-11 Siemens Ag Hardware independent mapping of multiple sensor configurations for classification of persons
JP4474995B2 (en) * 2004-04-28 2010-06-09 株式会社デンソー Vehicle seating sensor
EP1818208A1 (en) * 2006-02-08 2007-08-15 IEE INTERNATIONAL ELECTRONICS & ENGINEERING S.A. Vehicule seat with pressure activatable sensor
JP5083605B2 (en) * 2006-11-29 2012-11-28 株式会社デンソー Load sensor
JP4434259B2 (en) * 2007-10-31 2010-03-17 株式会社デンソー Seating sensor
JP4629124B2 (en) * 2008-04-03 2011-02-09 株式会社デンソー Seating sensor
DE102008053626B4 (en) * 2007-10-31 2016-09-08 Denso Corporation Seat sensor
JP4877358B2 (en) * 2009-05-08 2012-02-15 株式会社デンソー Seating sensor

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO2011033360A1 *

Also Published As

Publication number Publication date
CN102498018A (en) 2012-06-13
WO2011033360A1 (en) 2011-03-24
JP2011063076A (en) 2011-03-31

Similar Documents

Publication Publication Date Title
WO2011033360A1 (en) Vehicle seat occupancy sensor
US7918144B2 (en) Seating sensor
US20050140210A1 (en) Occupant detection system
JP4229071B2 (en) Capacitive sensor and occupant detection system
CN101423035B (en) Seating sensor
US6831565B2 (en) Seat occupation judging apparatus for a vehicle
US20110010109A1 (en) Vehicle tilt detecting apparatus and seat load detecting apparatus using the same
EP2329998B1 (en) Seat occupancy detection device
US20050216158A1 (en) Occupant-classifying system
WO2013080369A1 (en) Load detection device
EP1155292B1 (en) Method and apparatus for sensing seat occupant weight
JP2010159043A (en) Occupant detection system
US7135645B2 (en) Occupant weight detecting device
JP5019099B2 (en) Vehicle seat occupant discrimination device
JP2006298039A (en) Occupant seating posture detection system and seat for automobile
JPH11334451A (en) Occupant detector
US20080122644A1 (en) Seat sensor
US7222879B2 (en) Seating condition detecting system for vehicle
KR20180083573A (en) Seat belt reminder mat sensor for detecting passenger in center of rear seat
JP5499491B2 (en) Occupant detection sensor and occupant detection system
JP4065244B2 (en) Occupant detection device
JP2000296757A (en) Operation control system for vehicle occupant protection device
JP2009220727A (en) Seating sensor, seating detection device, and vehicle seat
JP2002087132A (en) Seating detection device
JPH11198705A (en) Occupant detection device

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 20120329

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO SE SI SK SM TR

DAX Request for extension of the european patent (deleted)
STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION HAS BEEN WITHDRAWN

18W Application withdrawn

Effective date: 20130117