U.S. patent application number 10/644042 was filed with the patent office on 2004-02-26 for seat load measuring apparatus.
This patent application is currently assigned to TAKATA CORPORATION. Invention is credited to Kajiyama, Hiroshi, Kobata, Toshihiko.
Application Number | 20040035224 10/644042 |
Document ID | / |
Family ID | 31191884 |
Filed Date | 2004-02-26 |
United States Patent
Application |
20040035224 |
Kind Code |
A1 |
Kajiyama, Hiroshi ; et
al. |
February 26, 2004 |
Seat load measuring apparatus
Abstract
A seat load measuring apparatus which can be effectively adopted
to various kinds of motor vehicles without requiring various load
sensors having cables of different lengths according to the kinds
of motor vehicles, thereby providing improved installation,
maintenance and manufacturing benefits. A seat load measuring
apparatus may include a connector of a load sensor is a male
connector having terminals projecting downwardly. The entry of the
male connector faces the open bottom of a protector. On the other
hand, a cable to be connected to an ECU is provided with a
cable-side connector. The cable-side connector is composed of a
female connector which is detachable relative to the male
connector. Therefore, the load sensor and the cable are detachable
from each other, thereby achieving the adaptability of the load
sensor and the connector casing a relative to various kinds of
motor vehicles.
Inventors: |
Kajiyama, Hiroshi;
(Hikone-shi, JP) ; Kobata, Toshihiko;
(Omihachiman, JP) |
Correspondence
Address: |
FOLEY AND LARDNER
SUITE 500
3000 K STREET NW
WASHINGTON
DC
20007
US
|
Assignee: |
TAKATA CORPORATION
|
Family ID: |
31191884 |
Appl. No.: |
10/644042 |
Filed: |
August 20, 2003 |
Current U.S.
Class: |
73/862.474 |
Current CPC
Class: |
B60R 21/0152 20141001;
B60N 2/0732 20130101; B60R 21/01516 20141001; B60N 2/002 20130101;
G01G 19/4142 20130101; B60N 2/0715 20130101 |
Class at
Publication: |
73/862.474 |
International
Class: |
G01L 001/22 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 21, 2002 |
JP |
2002-240096 |
Nov 8, 2002 |
JP |
2002-324758 |
Jul 4, 2003 |
JP |
2003-191694 |
Claims
What is claimed is:
1. A seat load measuring apparatus comprising: a load sensor for
detecting a load which is applied to a vehicle seat by an occupant
sitting on said vehicle seat; a control unit for calculating the
load applied to said vehicle seat on the basis of a detection
signal of said load sensor; and a distortion member which is
distorted due to the load applied on said vehicle seat; a plurality
of strain gauges for detecting the distortion of said distortion
member; and a sensor-side connector connected to said plurality of
strain gauges and adapted to be connected to a cable to carry a
signal from the sensor to the control unit.
2. The apparatus of claim 1, wherein said sensor-side connector is
configured to allow the cable to be detachably connected.
3. The apparatus of claim 2, further comprising: a base frame, upon
which said load sensor is disposed, which is fixed to a vehicle
floor or a lower member of said vehicle seat, wherein the base
frame receives the load applied on said vehicle seat.
4. The apparatus of claim 3, wherein said base frame includes a
protector for protecting at least a part of said load sensor
including said sensor-side connector.
5. The apparatus of claim 4, wherein said protector includes an
open side facing in at least one of the vertical direction, the
longitudinal direction, the lateral direction, the diagonal
direction from upper front to lower back or from lower front to
upper back, the diagonal direction from upper left to lower right
or from lower left to upper right, and the diagonal direction from
forward left to backward right or from backward left to forward
right in a state mounted to the vehicle, and the entry of said
sensor-side connector faces the open side of said protector.
6. The apparatus of claim 4, wherein said protector is formed by
bending a band-like plate to have a protecting portion surrounding
at least a part of said load sensor including said sensor-side
connector, and mounting portions to be attached to said base
frame.
7. The apparatus of claim 3, further comprising: a plurality of
front-side and rear-side rail brackets which are disposed near the
front and rear ends of said base frame, respectively; a seat rail
connected to said front-side and rear-side rail brackets which
slides in the longitudinal direction of the vehicle; and a
plurality of arms which are disposed on a front portion and a rear
portion of said base frame, respectively to extend in the
longitudinal direction.
8. The apparatus of claim 7, wherein each of said plurality of arms
is provided at its one end with a press portion for transmitting
force to said plurality of strain gauges and at its other end with
a connecting portion relative to each of said plurality of rail
brackets.
9. The apparatus of claim 7, further comprising: a plurality of
protective mechanisms that are disposed around said plurality of
front and rear rail brackets, respectively, such that when the load
applied between said base frame and said plurality of rail brackets
exceeds a predetermined value, said plurality of protective
mechanisms directly transmit the excessive load between said base
frame and said plurality of rail brackets not through said
plurality of arms.
10. The apparatus of claim 9, further comprising a reinforcing
member disposed on said plurality of protective mechanisms at the
rear-side rail bracket for providing reinforcement against the load
in a direction of lifting said base frame.
11. A seat load measuring apparatus comprising: a load sensor for
detecting a load which is applied to a vehicle seat, wherein the
load sensor includes a connector configured to connect to a cable
to carry a signal from the sensor to a control unit; wherein the
connector is configured to allow the cable to be detachably
connected so that the cable can be connected to the measuring
apparatus after the apparatus is installed in the vehicle.
12. The apparatus of claim 11, further comprising a protecting
member that protects the connector from damage due to lifting of a
rear side of the vehicle seat.
13. The apparatus of claim 12, wherein the protecting member
includes an opening for receiving an end of the cable
therethrough.
14. The apparatus of claim 11, wherein the load sensor includes a
distortion member configured to be distorted when load is applied
to the seat.
15. The apparatus of claim 14, wherein the load sensor includes a
strain gauge for detecting the amount of distortion of the
distortion member.
16. A seat load measuring apparatus comprising a load sensor for
detecting a load which is applied to a vehicle seat by measuring
the amount of distortion of a distortion member using a strain
gauge, wherein the load sensor includes a sensor-side connector
configured to be detachably connected to a cable having a
corresponding cable-side connector to carry a signal from the
sensor to a control unit; and a protecting member that is arranged
to protector the sensor from a large load resulting from lifting of
a rear side of the vehicle seat.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a seat load measuring
apparatus for measuring a seat load applied to a seat of a vehicle,
such as an automobile, by the weight of an occupant sitting on the
seat. Particularly, the present invention pertains to a seat load
measuring apparatus which can be flexibly and effectively adopted
to various kinds of motor vehicles.
[0002] A conventional automobile is equipped with seat belt devices
and airbag devices. These devices are provided for restraining the
inertial movement of occupants so as to protect the occupants in
the event of an emergency such as a vehicle collision at which
large deceleration is exerted on the vehicle.
[0003] The amount of the inertial force acting on the occupant
depends on the weight of the occupant sitting on the vehicle seat.
If the seat belt device and the airbag device are invariably
controlled regardless of the weight of the occupant, it is
difficult to make these devices effectively restrain the occupant
in relation to the inertial force acting on the occupant. In recent
years, there has been a proposal to control the actions of these
safety devices based on the weight (body weight) of an occupant
sitting in a vehicle seat in order to make the seat belt device and
the airbag device restrain the occupant more effectively. For
example, adjusting the amount of gas for deploying the airbag, the
airbag inflating speed, and/or the magnitude of pretension of the
seat belt depending on the weight of the occupant.
[0004] In order to control the actions of the seat belt device and
the airbag device depending on the weight of the occupant sitting
on the vehicle seat, it is necessary to measure the weight of the
occupant. To achieve this, it has been proposed that a vehicle seat
be provided with a seat load measuring apparatus for measuring the
weight of an occupant sitting on the vehicle seat.
[0005] The seat load measuring apparatus requires load sensors for
detecting the magnitude of load applied to the vehicle seat by the
weight of the occupant. There are some seat load measuring
apparatuses employing strain gauges as the load sensors (for
example, see Japanese Unexamined Patent Publication No. H11-304579,
Japanese Unexamined Patent Publication No. H11-351952, Japanese
Patent Unexamined Publication No. 2001-304949) (both of which are
incorporated by reference herein in their entireties).
[0006] Load sensors to be used for this purpose require a high
degree of detection accuracy and adequate fracture strength. In
general, the load sensor should have a detection accuracy that
enables it to detect a load fluctuation of about 100 g in the
gravitational direction. The accuracy must not be affected even
when a load of 100 kg is applied in any direction other than the
gravitational direction. In regards to the strength of the load
sensor, it is required that the sensor effectively and securely
withstand a large load in the event of a vehicle collision.
[0007] One problem frequently encountered is that in the event of a
vehicle collision, large deceleration may act on a vehicle body so
as to momentarily lift up the rear side of a vehicle seat where the
seat load measuring apparatus is mounted.
[0008] For an apparatus with a strain gauge as a load sensor, the
gauge, disposed on a sensor plate is deflected and deformed
depending on the magnitude of load applied to the vehicle seat. The
sensor plate is connected to a cable which connects to an
electronic control unit (ECU) mounted on the vehicle so that a
casing for the load sensor and the cable are united. However,
different types of vehicles require the cable to be different
lengths. Therefore, manufacturers must produce load sensors with
varying cable lengths resulting in an increase in production
costs.
[0009] Further, since the cable is attached to the load sensor, it
is troublesome to mount the sensor plate to the body of the load
sensor. As a result, such a seat load measuring apparatus is
difficult to install, maintain and manufacture.
SUMMARY OF THE INVENTION
[0010] It is one of several objects of the present invention to
provide a seat load measuring apparatus which can be adapted for
use in various kinds of motor vehicles without requiring various
load sensors to have cables of different lengths. Thus, the present
invention provides improved compatibility and is more efficient to
produce. Additionally, it is an object of the present invention to
provide an inexpensive seat load measuring apparatus, which can be
adapted for use in various kinds of motor vehicles that also
withstands a large load applied to the mounting portion of the seat
load measuring apparatus due to the lifting of the rear side of the
vehicle seat.
[0011] In the following description of the various embodiments of
the present invention, the forward, backward, leftward, rightward,
upward, and downward directions correspond to the forward,
backward, leftward, rightward, upward, and downward directions of a
vehicle.
[0012] A seat load measuring apparatus according to one embodiment
of the present invention includes a load sensor detecting a load
which is applied to a vehicle seat by an occupant sitting on the
vehicle seat; a control unit for calculating the load applied to
the vehicle seat on the basis of a detection signal of the load
sensor; and a cable connecting the load sensor and the control unit
to transmit the detection signal of the load sensor to the control
unit, and is characterized in that the load sensor has a distortion
member which is distorted due to the load applied on the vehicle
seat, strain gauges for detecting the distortion of the distortion
member, and a sensor-side connector connected to the strain gauges,
and the cable has a cable-side connector which is detachably
connected to the sensor-side connector.
[0013] A seat load measuring apparatus according to one embodiment
of the present invention further comprises a base frame which is
fixed to a vehicle floor or a lower member of the vehicle seat and
on which the load applied on the vehicle seat acts, the load sensor
being disposed on the base frame, wherein the base frame is
provided with a protector for protecting at least a part of the
load sensor including the sensor-side connector, the protector is
open in at least one side in any of the vertical direction, the
longitudinal direction, the lateral direction, the diagonal
direction from upper front to lower back or from lower front to
upper back, the diagonal direction from upper left to lower right
or from lower left to upper right, and the diagonal direction from
forward left to backward right or from backward left to forward
right in a state mounted to the vehicle, and the entry of the
sensor-side connector faces the open side of said protector.
[0014] According to one embodiment of the present invention the
protector is formed by bending a band-like plate to have a
protecting portion surrounding at least a part of the load sensor
including the sensor-side connector, and mounting portions to be
attached to the base frame.
[0015] According to one embodiment of the present invention the
seat load measuring apparatus further comprises front-side and
rear-side rail brackets which are disposed near the front and rear
ends of the base frame, respectively, and are connected to a seat
rail which slides in the longitudinal direction of the vehicle; and
arms which are disposed on a front portion and a rear portion of
the base frame, respectively to extend in the longitudinal
direction and each of which is provided at its one end with a press
portion for transmitting force to said strain gauges and at its
other end with a connecting portion relative to each rail bracket,
and wherein protective mechanisms are disposed around the front and
rear rail brackets, respectively, and when the load applied between
the base frame and said rail brackets exceeds a predetermined
value, the protective mechanisms directly transmit the excessive
load between the base frame and the rail brackets not through the
arms, and the protective mechanism at the rear-side rail bracket is
provided with a reinforcing member for providing reinforcement
against the load in a direction of lifting the base frame.
[0016] According to one embodiment of the present invention a cable
for connecting a load sensor and a control unit can be designed to
be detachable by employing a sensor-side connector and a cable-side
connector, thereby achieving the adaptability of the load sensor
and the connector casing relative to various kinds of motor
vehicles. The only preparation required is configuring a cable
having a length corresponding to the kind of motor vehicle.
Therefore, the seat load measuring apparatus can be easily and
inexpensively adopted to various kinds of motor vehicles.
[0017] According to one embodiment of the present invention, by
utilizing an opening of a protector which is formed in at least one
side in any of the vertical direction, the longitudinal direction,
the lateral direction, the diagonal direction from upper front to
lower back or from lower front to upper back, the diagonal
direction from upper left to lower right or from lower left to
upper right, and the diagonal direction from forward left to
backward right or from backward left to forward right, the load
sensor can be effectively protected and the connection and
disconnection between the load sensor and the cable can be
facilitated. Moreover, it is not required to form hole(s) and
groove(s) for insertion of the cable-side connector, thus further
simplifying the manufacture and reducing the cost.
[0018] According to one embodiment of the present invention, the
sensor-side connector and the cable-side connector can be delivered
in the connected state. In addition, since the connectors are
allowed to be connected during the assembly of a vehicle body by a
car manufacturer, the connectors can be delivered separately.
Moreover, the flexibility during manufacturing process is improved.
In this manner, an inexpensive seat load measuring apparatus which
can be effectively adopted in various kinds of motor vehicles and
is easier to install, maintain and manufacture.
[0019] Further, according to one embodiment of the present
invention, the protector is formed just by bending a band-like
plate. Therefore, the protector can be easily and inexpensively
formed. Furthermore, according to one embodiment of the present
invention, a protective mechanism is provided so as to effectively
withstand large load exerted on the mounting portion of the seat
load measuring apparatus disposed between a vehicle seat and a
vehicle floor by a moment in a direction of lifting the rear
portion of the vehicle seat.
[0020] It is to be understood that both the foregoing general
description and the following detailed description are exemplary
and explanatory only, and are not restrictive of the invention as
claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] These and other features, aspects, and advantages of the
present invention will become apparent from the following
description, appended claims, and the accompanying exemplary
embodiments shown in the drawings, which are briefly described
below.
[0022] FIG. 1 is a side view schematically showing a vehicle seat
provided with a seat load measuring apparatus according to one
embodiment of the present invention.
[0023] FIG. 2 is an exploded perspective view showing the seat load
measuring apparatus according to one embodiment of the present
invention.
[0024] FIGS. 3(A), 3(B) show the seat load measuring apparatus of
one embodiment of the present invention in the assembled state
thereof, wherein FIG. 3(A) is a plan view thereof and FIG. 3(B) is
a sectional view taken along a line IIIB-IIIB of FIG. 3(A).
[0025] FIG. 4 is an exploded perspective view showing a sensor
portion of the seat load measuring apparatus of one embodiment of
the present invention.
[0026] FIGS. 5(A), 5(B) are enlarged partial views of a portion
about the sensor portion in the seat load measuring apparatus of
one embodiment of the present invention.
[0027] FIGS. 6(A), 6(B) show a rear end portion of the seat load
measuring apparatus of one embodiment of the present invention,
wherein FIG. 6(A) is an exploded view thereof and FIG. 6(B) is an
assembled view thereof.
[0028] FIGS. 7(A), 7(B) show a bolt mounting portion of the seat
load measuring apparatus of one embodiment of the present
invention, wherein FIG. 7(A) is an enlarged sectional view taken
along the axis of a front stopper bolt and FIG. 7(B) is an enlarged
sectional view taken along the axis of a pivot bolt.
[0029] FIG. 8 is an enlarged sectional view showing a portion near
a double sleeve of the seat load measuring apparatus of one
embodiment of the present invention.
[0030] FIGS. 9(A), 9(B) show an example of a rear end portion of a
base frame of a seat load measuring apparatus as a comparative
example relative to one embodiment of the present invention,
wherein FIG. 9(A) is a side sectional view showing the normal state
and FIG. 9(B) is a side sectional view showing a state after a
force in a direction of lifting the seat is exerted.
[0031] FIGS. 10(A), 10(B) show the rear end portion of the base
frame of the seat load measuring apparatus of one embodiment of the
present invention shown in FIG. 2, wherein FIG. 10(A) is a side
sectional view showing the normal state and FIG. 10(B) is a side
sectional view showing a state after a force in a direction of
lifting the seat is exerted.
[0032] FIG. 11 is a partial enlarged perspective view of the sensor
portion of the seat load measuring apparatus of one embodiment of
the present invention shown in FIG. 2.
[0033] FIG. 12 is a partial plan view of the sensor portion of the
seat load measuring apparatus of one embodiment of the present
invention shown in FIG. 2.
[0034] FIG. 13 is a sectional view taken along a line XIII-XIII of
FIG. 12.
[0035] FIG. 14 is a sectional view taken along a line XIV-XIV of
FIG. 12.
[0036] FIG. 15 is a perspective view partially showing a connector
casing of one embodiment of the present invention.
[0037] FIGS. 16(A)-16(D) show a variation example of the rear end
portion of the base frame of one embodiment of the present
invention shown in FIGS. 10(A), 10(B), wherein FIG. 16(A) is a side
sectional view showing the normal state, FIG. 16(B) is a sectional
view taken along al line XVIB-XVIB of FIG. 16(A), FIG. 16(C) is a
side sectional view showing a state after a force in a direction of
lifting the seat is exerted, and FIG. 16(D) is a sectional view
taken along a line XVID-XVID of FIG. 16(C).
[0038] FIGS. 17(A)-17(D) show another variation example of the rear
end portion of the base frame of one embodiment of the present
invention shown in FIGS. 10(A), 10(B), wherein FIG. 17(A) is a side
sectional view showing the normal state, FIG. 17(B) is a sectional
view taken along al line XVIIB-XVIIB of FIG. 17(A), FIG. 17(C) is a
side sectional view showing a state after a force in a direction of
lifting the seat is exerted, and FIG. 17(D) is a sectional view
taken along a line XVIID-XVIID of FIG. 17(C).
[0039] FIG. 18 is an exploded perspective view similar to FIG. 4,
but showing a variation example of the sensor portion shown in FIG.
4.
[0040] FIGS. 19(A), 19(B) show a variation example of the sensor
portion of the seat load measuring apparatus, wherein FIG. 19(A) is
a partial plan view similar to FIG. 12 and FIG. 19(B) is a
sectional view similar to FIG. 13, taken along a line XIXB-XIXB of
FIG. 19(A).
DETAILED DESCRIPTION
[0041] One of many embodiments of the present invention will be
described below with reference to the drawings.
[0042] As shown in FIG. 1, a vehicle seat 1 has a seat cushion 1a
on which an occupant sits, and a seat pan 2 made of a steel plate
which is disposed beneath the seat cushion 1a to entirely cover the
under surface of the seat cushion 1a. Under the seat pan 2, a pair
of side frames 3 (only one of which is shown in FIG. 1) extend
downwardly from the seat pan 2 and are spaced apart from each other
at a predetermined distance in the lateral (left-to-right)
direction of the vehicle. Each side frame 3 is disposed to extend
in the longitudinal (front-to-rear) direction of the vehicle.
Disposed on the lower ends of the side frames 3 are seat rails 8
(only one of which is shown in FIG. 1), respectively. Each seat
rail 8 is a combination of an upper rail 11 which is fixed to the
lower end of the side frame 3 and a lower rail 15 which is arranged
to slide relative to the upper rail 11 in the longitudinal
direction of the vehicle.
[0043] Disposed on the under surfaces of the lower rails 15 are
seat load measuring apparatuses 10 (only one of which is shown in
FIG. 1). Each seat load measuring apparatus is connected to each
lower rail 15 via a pair of front and rear rail brackets 35, 45.
The seat load measuring apparatuses 10 are fixed to a pair of seat
brackets 9 (only one of which is shown in FIG. 1) which are secured
to a vehicle floor 7 and spaced apart from each other in the
lateral direction of the vehicle.
[0044] As shown in FIG. 2 and FIGS. 3(A), 3(B), the seat load
measuring apparatus 10 comprises a base frame 21 which extends in
the longitudinal direction of the vehicle. The base frame 21 is
composed of a base bottom 22 and base side walls 23L, 23R such that
the base frame 21 is formed to have an upward U-shaped cross
section (to have an open top). It should be noted that the base
frame 21 may be formed to have a downward U-shaped cross section
(to have an open bottom). The base frame 21 is provided near the
front and rear ends thereof with mounting portions 30 and 40
relative to the vehicle body or the seat rails, respectively, and
is provided at the center thereof with a sensor portion 50.
[0045] The mounting portion 30 at the front end side of the base
frame 21 is provided with a hole 22A (see FIG. 2) which is formed
in the base bottom 22 at a predetermined location and is provided
with elongated holes 32, pivot holes 33, and small apertures 31
which are formed in front end portions of the left and right base
side walls 23L, 23R, respectively to correspond to those of the
other base side-wall 23L, 23R. In FIG. 9(A) as will be described
later, the hole 22A is a hole for insertion of a riveting jig J.
The elongate holes 32 are long in the vertical direction. As shown
in FIG. 2, FIGS. 3(A), 3(B), and FIG. 7(A), a stopper bolt (pivot
pin) 24 is inserted through the elongated holes 32. The stopper
bolt 24 is a pivot pin which pivotally supports a rail bracket 35
and a Z arm 61Fr together and transmits a seat load to the Z arm
61Fr as shown in FIG. 3(B). The stopper bolt 24 is provided at one
end with a hexagon head 24H, at the other end with a threaded
portion 24S, and at the middle with a smooth cylindrical surface.
The stopper bolt 24 is inserted through the elongated holes 32 and
is then fixed by a stopper nut 24N via a stopper washer 24W.
[0046] As shown in FIG. 7(A), there is a gap between the stopper
bolt 24 and each elongate hole 32 in the assembled state so that
the stopper bolt 24 is normally prevented from touching the inner
peripheries of the elongated holes 32. However, when an excessive
load is applied to the vehicle seat 1, the stopper bolt 24 is
lowered to come in contact with the lower peripheries of the
elongate holes 32 so that the excessive load is transmitted
directly to the base side walls 23L, 23R of the base frame 21 from
the rail bracket 35. In this case, the excessive load is not
transmitted to a load sensor (sensor plate 52, as will be described
later) 51. Also, when the rail bracket 35 is lifted up because of
some effect of forces applied to the seat, the stopper bolt is
lifted up to come in contact with the upper peripheries of the
elongated holes 32 so as to exhibit the same works.
[0047] As shown in FIG. 2, the pivot holes 33 are formed in
positions closer to the center than the positions of the elongated
holes 32. Formed around the pivot holes 33 are counter bores 33a
formed in outer surfaces of the base side walls 23L, 23R and
convexities 33b formed in the inner surfaces of the base side walls
23L, 23R. Inserted into the pivot holes 33 is a pivot bolt (pivot
pin) 25 as shown in FIG. 2, FIGS. 3(a), 3(B), and FIG. 7(B). The
pivot bolt 25 is a pivot pin for supporting the Z arm 61Fr such
that the Z arm 61Fr pivots relative to the base frame 21. When the
seat load is applied to the Z arm 61Fr as shown in FIG. 3(B), the Z
arm 61Fr pivots about the pivot bolt 25. The pivot bolt 25 is
provided at one end with a hexagon head 25H, at the other end with
a threaded portion 25S, and at the middle with a smooth cylindrical
surface. The pivot bolt 25 is inserted through the pivot holes 33
and is then fixed by a pivot nut 25N.
[0048] Since the stopper bolt 24 and the pivot bolt 25 are of type
to be fastened by the nuts 24N and 25N, these are easily and
securely attached. The small apertures 31 formed adjacent to the
pivot holes 33 are service windows for observation of the
assembling state.
[0049] As shown in FIG. 2 and FIGS. 3(A), 3(B), the Z arm 61Fr is
arranged inside the base frame 21 at the mounting portion 30 at the
front end side of the base frame 21. The Z arm 61Fr has a portion
on the rear side from the middle portion, which is forked into two
plate-shape branches 66, when seen in plain view. The Z arm 61Fr
has a portion on the front side, where arm side plates 67L, 67R are
formed to stand upwardly from the left and right edges. As shown in
FIGS. 3(A), 3(B) and FIGS. 7(A), 7(B), the Z arm 61Fr is assembled
between the base side walls 23L and 23R to extend along the inner
surfaces of the base side walls 23L and 23R. There are gaps between
the arm side plate 67L and the base side wall 23L and between the
arm side plate 67R and the base side wall 23R so that flanges of
sleeves 70 (71, 72) and 75 are disposed in these gaps
[0050] As shown in FIG. 2, each of the side plates 67L, 67R of the
Z arm 61Fr is provided with holes 62, 63 formed at locations
corresponding to the elongate hole 32 and the pivot hole 33 of the
base side wall 23L, 23R. As shown in FIG. 2, FIGS. 3(A), 3(B), FIG.
7(A), 7(B), inserted into the holes 62 (corresponding to the
elongate holes 32 of the base frame 21) formed near the front end
of the Z arm 61Fr is the stopper bolt 24. Inserted into the holes
63 (corresponding to the pivot holes 33 of the base frame 21) at
the middle portion side of the Z arm 61Fr is the pivot bolt 25.
[0051] The main task of the stopper bolt 24 is connecting the rail
bracket 35 and the Z arm 61Fr in such a manner as to allow the
pivotal movement of them and transmitting a seat load to the Z arm
61Fr as can be seen in FIG. 3(B). Since there are gaps between the
stopper bolt 24 and the elongated holes 32, the base frame 21 and
the stopper bolt 24 are normally prevented from interfering each
other. On the other hand, the main task of the pivot bolt 25 is
pivotally supporting the Z arm 61Fr relative to the base frame 21,
whereby the Z arm 61 can pivot about the pivot bolt 25.
[0052] The branches 66 of the Z arm 61Fr are designed to have a
smaller distance between them at the middle portion side. As shown
in FIG. 2 and FIGS. 3(A), 3(B), a ridge portion 61a is formed in
the middle portion of the Z arm 61Fr, thereby increasing the
strength of the Z arm 61Fr. Action portions at the ends (rear ends)
of the branches 66 are covered by resin arm caps 66A, respectively.
The resin arm caps 66A are sandwiched between wings 53a, 55a of
upper and lower half arms 53, 55 (see FIG. 5(B)) of the load sensor
51 (as will be described later). Because of the arm caps 66A,
noises (contact noise between metals) generated when the action end
portions of the Z arm 61Fr collide with the wings 53a, 55a of the
half arms 53, 55 can be nearly completely absorbed, thereby
preventing the occupants sitting on the vehicle seat 1 from hearing
jarring sounds. As a load is exerted on the rail bracket 35, the Z
arm 61Fr slightly pivots, whereby the action end portions transmit
the load to the sensor plate 52 (corresponding to the distortion
member of the present invention) through the half arms 53, 55.
[0053] At the mounting portion 30 at the front end side, the front
rail bracket 35 is assembled inside the Z arm 61Fr. As shown in
FIG. 2, FIGS. 3(A), 3(B), and FIG. 7(A), the front rail bracket 35
is composed of a flat top portion 36 and side walls 37L, 37R
extending downwardly from the left and right edges of the top
portion 36 in such a manner as to have an inverted U-shaped cross
section. The lower rail 15 of the seat rail 8 is mounted on the
upper surface of the top portion 36. In this case, the top portion
36 has a hole 36a formed therein through which a rivet fastening
the top portion 36 and the seat rail 8 together is inserted.
[0054] Each of the left and right side plates 37L, 37R of the front
rail bracket 35 is substantially formed in a trapezoidal shape. The
left and right side plates 37L, 37R have holes 38, respectively, to
face each other. The holes 38 are formed at locations corresponding
to the elongate holes 32 of the base side walls 23L, 23R and the
holes 62 of the Z arm 61Fr. In the assembled state, inserted into
the holes 38 is the stopper bolt 24 as shown in FIGS. 3(A), 3(B),
and FIG. 7(A).
[0055] As shown in FIG. 7(A) and FIG. 8, double sleeves 70 are
fitted around the outer periphery of the cylindrical portion of the
stopper bolt 24. Each of the double sleeve 70 comprises an inner
sleeve 71 which is longer and an outer sleeve 72 which is shorter
and fitted around the inner sleeve 71. The sleeves 71, 72 have
flanges 71a, 72a at one ends and tapered portions 71b, 72b (see
FIG. 8) at the other ends. The inner surfaces of the sleeves 71, 72
and the end faces of the flanges 71a, 72a are coated with
Teflon.RTM.. It should be noted that FIG. 8 shows the inclinations
of the tapered portions 71b, 72b in an exaggerated way.
[0056] The inner sleeve 71 of the double sleeve 70 is fitted into a
space between the shaft portion of the stopper bolt 24 and the hole
62 of the arm side plate 67L (67R) and a space between the shaft
portion of the stopper bolt 24 and the hole 38 of the front rail
bracket 35. The outer sleeve 72 is press fitted between the outer
periphery of the inner sleeve 71 and the hole 38 of the front rail
bracket 35. The flange 72a of the outer sleeve 72 is disposed
between the arm side plate 67L (67R) and the side plate 37L (37R)
of the front rail bracket 35. The flange 71a of the inner sleeve 71
abuts on the outer surface of the arm side plate 67L (67R).
[0057] Now, the relation between the double sleeve 70 and the
peripheral components and the works of the double sleeve 70 will be
explained with reference to FIG. 8. Since the inner sleeve 71 is
press fitted into the hole 62 of the arm side plate 67L (67R), the
inner sleeve 71 is prevented from rattling within the hole 62.
Between the inner sleeve 71 and the stopper bolt 24 inserted
through the inner bore of the inner sleeve 71, the tapered portion
71b of the inner sleeve 71 is elastically in contact with and
supports the outer periphery of the stopper bolt 24. Therefore,
while there is a clearance between a portion of the inner sleeve 71
other than the tapered portion 71b and the stopper bolt 24, the
stopper bolt 24 is prevented from rattling within the inner bore of
the inner sleeve 71.
[0058] Between the outer sleeve 72 and the inner sleeve 71 fitted
in the inner bore of the outer sleeve 72, the tapered portion 72b
of the outer sleeve 72 is elastically in contact with and supports
the outer periphery of the inner sleeve 71. Therefore, while there
is a clearance between a portion of the outer sleeve 72 other than
the tapered portion 72b and the inner sleeve 72, the inner sleeve
71 is prevented from ratting within the inner bore of the outer
sleeve 72.
[0059] Accordingly, there is no clearance allowing the ratting of
the components between the side plate 37 of the front rail bracket
35 and the stopper bolt 24, thereby preventing the occurrence of
noise (contact noise between metals) generated due to the rattling
of these components when the weight applied to the seat is
varied.
[0060] Now, description will be made as regard to the peripheral
components of the pivot bolt 25 as the pivot for the Z arm 61Fr and
the front rail bracket 35. As shown in FIG. 7(B), sleeves 75 are
fitted around the outer periphery of the cylindrical portion of the
pivot bolt 25. Each sleeve 75 has a flange 75a at its one end and a
tapered portion 75b at its other end. The inner surface of the
sleeve 75 and the end face of the flange 75a are coated with
Teflon.RTM..
[0061] Since the sleeve 75 is press fitted into the hole 63 of the
arm side plate 67L (67R), the inner sleeve 75 is prevented from
rattling within the hole 63. Between the sleeve 75 and the pivot
bolt 25 fitted in the inner bore of the sleeve 75, the tapered
portion 75b of the sleeve 75 is elastically in contact with and
supports the outer periphery of the pivot bolt 25. Therefore, while
there is a clearance between a portion of the sleeve 75 other than
the tapered portion 75b and the pivot bolt 25, the stopper bolt 25
is prevented from rattling within the inner bore of the sleeve 75.
Accordingly, the occurrence of noise generated due to the rattling
of the pivot bolt 25 and/or the Z arm 61Fr when the load applied to
the seat is varied can be prevented.
[0062] Next, the mounting portion 40 at the rear end side of the
base frame 21 will be explained. The different point of the
mounting portion 40 at the rear end side of the base frame from the
aforementioned mounting portion 30 at the front end side of the
base frame is that the mounting portion 40 at the rear end side of
the base frame has two stopper bolts as the protective mechanism
for transmitting excessive load from the rear rail bracket 45 to
the base frame 21, thereby having higher loading capacity than the
mounting portion 30 at the front end side of the base frame.
[0063] That is, the mounting portion 40 at the rear end side is
provided with a front-side first stopper bolt 26 and a rear-side
second stopper bolt 28. The front-side stopper bolt 26
(hereinafter, sometime called as "front stopper bolt 26") has the
same components as those of the stopper bolt 24 of the mounting
portion 30 at the front side mentioned above so that the same
appendices as those of the numeral "24" are added to the numeral
"26" and detail descriptions of the components are omitted. The
rear-side second stopper bolt 28 (hereinafter, sometime called as
"rear stopper bolt 28") is an additional reinforcing member which
is not used in the mounting portion 30 at the front end side. The
following description will center on the structure of the second
stopper bolt 28 as an additional member and the related
components.
[0064] The base frame 21 has circular holes 44, adjacent to
elongated holes 42 and nearer to the rear end thereof than the
elongated holes 42, through which the rear stopper bolt 28 is
inserted. Each circular hole 44 has such a diameter as to allow the
insertion of the shaft portion of the rear stopper bolt 28. As
shown in FIG. 2 and FIGS. 6(A), 6(B), the rear stopper bolt 28 is
provided at one end with a hexagon head 28H, at the other end with
a threaded portion 28S, and at the middle with a smooth cylindrical
surface. The rear stopper bolt 28 is fixed by a stopper nut 28N as
shown in FIG. 3(A) and FIG. 6(B) when assembled. In the assembled
state, there are spaces between the hexagon head 28H of the rear
stopper bolt 28 and an outer surface of the base side wall 23 and
between a bearing surface of the stopper nut 28N and an outer
surface of the base side wall 23. Connecting portions 9b of the
seat bracket (seat legs) 9 as shown in FIGS. 10(A), 10(B) as will
be described later are situated in these spaces.
[0065] A Z arm 61Rr to be arranged inside the rear side portion of
the base frame 21 has the same structure as the aforementioned Z
arm 61Fr arranged in the front side portion of the base frame and
comprises branches 66, arm side plates 67L, 67R, and arm caps 66A
of action portions at the ends thereof. As shown in FIG. 2 and
FIGS. 3(A), 3(B), the Z arm 61Fr at the front end side of the base
frame and the Z arm 61Rr at the rear end side of the base frame are
arranged symmetrically about the center of the base.
[0066] The rear rail bracket 45 is arranged inside the Z arm 61Rr.
As shown in FIG. 2 and FIGS. 6(A), 6(B), the rear rail bracket 45
is composed of a flat top portion 46 and side walls 47L, 47R
extending downwardly from the left and right edges of the top
portion 46 in such a manner as to have an inverted U-shaped cross
section. The lower rail 15 of the seat rail 8 is mounted on the
upper surface of the top portion 46. In this case, the top portion
46 has two hole 46a formed therein through which rivets 15R (see
FIGS. 10(A), 10(B)) fastening the top portion 46 and the lower rail
15 together are inserted.
[0067] Each of the side plates 47L, 47R of the rear rail bracket 45
is substantially formed in a trapezoidal shape. Each of the left
and right side plates 47L, 47R have holes 48 and elongate holes 49
at locations corresponding to the elongated holes 42 and the
circular holes 44 of the base side walls 23L, 23R. As shown in FIG.
2, FIGS. 3(A), 3(B), and FIG. 7(A), the front stopper bolt 26 is
inserted through the holes 48 (corresponding to the elongate holes
42 and the holes 62 of the Z arm 61Rr). As shown in FIG. 7(A) and
FIG. 8, double sleeves 70 are inserted through spaces between the
front stopper bolt 26 and the hole 48 of the rear rail bracket 45
and between the front stopper bolt 26 and the hole 62 of the Z arm
61Rr similarly to the aforementioned case. In this case, the front
stopper bolt 26 is loosely fitted to the elongate holes 42 of the
base frame 21.
[0068] The rear stopper bolt 28 is inserted through the elongate
holes 49 (corresponding to the circular holes 44) of the rear rail
bracket 45 with suitable predetermined gaps. The works of the
mounting portion 40 at the rear end side of the base frame 21 will
be described later.
[0069] Hereinafter, the sensor portion 50 of the base frame 21 will
be described. As shown in FIG. 2, each of the left and right base
side walls 23L, 23R is formed with a notch 23X at the middle in the
longitudinal direction of the base frame 21. A protector 29 which
overhangs in the leftward direction is fixed to the outer surface
of the left base side wall 23L. As shown in FIG. 11, the protector
29 is formed by bending a band-like plate to have a protecting
portion 29a, formed in a U-like or C-like shape, and mounting
flanges 29b, 29c formed on both sides of the protecting portion
29a. A load sensor 51 is installed inside the notches 23X of the
base frame 21 and the protector 29.
[0070] That is, in a state that the mounting flanges 29b, 29c are
attached to the base side wall 23L as shown in FIG. 12, the
protecting portion 29a encloses and protects a portion of the load
sensor 51 projecting outside of the base side wall 23L through the
notch 23X of the base side wall 23L, i.e. a connector receiving
portion (see FIG. 11) of the sensor plate 52 and a connector casing
57a (see FIG. 11 and FIG. 12) of a sensor-side connector 57. The
connector casing 57a is attached to the upper surface of the
connector receiving portion by casing fixing screws 101, 102 (see
FIG. 11).
[0071] As shown in FIG. 5(B), in a state that the sensor plate 52,
the connector casing 57a, and the protector 29 are assembled in the
base frame 21, the level of the upper edge of the protector 29 is
higher than any of the level of the upper surface of the sensor
plate 52, the level of the upper surface of the connector casing
57a, and the level of the upper surface of the sensor-side
connector 57. The level of the lower edge of the protector 29 is
lower than any of the level of the lower surface of the sensor
plate 52, the level of the lower surface of the connector casing
57a, and the level of the lower surface of the sensor-side
connector 57. According to this design, the protector 29 can
securely protect precision components such as the sensor plate 52
and the connector 57 of the seat load measuring apparatus 10 even
if the base frame in which the seat load measuring apparatus 10 and
the protector 29 are assembled is dropped when the base frame 21 is
mounted to a vehicle or during transportation.
[0072] Since the upper side of the protector 29 is open, a cover
(not shown) is preferably provided to cover the upper side of the
protector 29 in order to further ensure the protection. The lower
side of the protector 29 is also open. However, since the object
matters are easily removed from the inside of the protector 29 even
if object matters enter into the protector 29, there is no
necessary to cover the lower side of the protector 29.
[0073] As shown in FIG. 15, the connector casing 57a has an opening
57f. Disposed around the peripheral edge, on the side to be in
contact with the sensor plate 52, of the opening 57f is a
watertight packing 57g. With the watertight packing 57g, the
connector casing 57a and the sensor plate 52 can be water-tightly
sealed. When potting is made on the opening 57f, the watertight
packing 57g also functions to prevent leakage of potting material.
The opening 57f is covered by resin, on the side not the side to be
in contact with the sensor plate 52, in order to prevent object
matters from entering through the opening 57f.
[0074] Since the upper side of the casing of the cable-side
connector 104 is also open, watertight packings 109, 110 are
provided to the casing of the cable-side connector 104 as shown in
FIG. 13 and FIG. 14. By these watertight packings 109, 110, the
upper side of the cable-side connector 104 is water-tightly sealed.
FIG. 12 and FIG. 13 show an example of structure for mounting the
sensor plate 52 to the base frame 21, this example being different
from the mounting structure composed of the components shown in
FIG. 4. That is, as shown in FIG. 13, the sensor plate 52 can be
attached to the base frame 21 just by screwing bolts into a
mounting base provided on the base bottom 22.
[0075] As shown in FIG. 4, the sensor plate 52 as the main
component of the load sensor 51 is a spring member which is a
rectangular plate having two necks 52c as a whole. At the left end
of the central portion of the sensor plate 52, the sensor-side
connector 57 is fixed by a vise 57a (see FIG. 5(A)). Connected to
the sensor-side connector 57 is an end of a cable connected to an
electronic control unit (ECU: corresponding to the control device
of the present invention) not shown.
[0076] On the sensor plate 52, an insulating layer for electrical
insulating, a wiring layer, and a resistive layer are formed. On
the sensor plate 52, as shown in FIG. 12, four strain resistors
105, 106, 107, 108 are formed as strain gauges which cooperate
together to compose the load sensor 51. The four strain resistors
105, 106, 107, 108 are connected to each other to form a bridge
circuit which is connected to the connector 57. In this case, as
shown in FIG. 12 and FIG. 13, terminals 57b, 57c of the connector
57 are connected to the conductors 52a, 52b of the bridge circuit
formed on the sensor plate 52 by the strain resistors.
[0077] As shown in FIG. 15, ends 57d, 57e, opposite to the side
connected to the conductors 52a, 52b, of the terminals 57b, 57c of
the connector 57 are disposed to project downwardly, thereby
forming a male connector 57. The terminals 57b, 57c of the
connector 57 are press-fitted into the connector casing 57a and are
thus united with the connector casing 57a.
[0078] As shown in FIG. 13 and FIG. 14, the connector 57 is
composed of a male connector 57 having terminals projecting
downwardly. The entry of the male connector 57 faces the open
bottom of the protector 29. On the other hand, as shown in FIG. 11,
the cable 103 to be connected to the ECU is provided with the
cable-side connector 104. The cable-side connector 104 is composed
of a female connector 57 which is detachable relative to the male
connector 57.
[0079] The cable 103 to be connected to the ECU is connected to the
cable-side connector 104. Therefore, in a state that the seat load
measuring apparatus 10 is attached to the base frame 21, the
cable-side connector 104 is inserted into the male connector 57
through the open bottom of the protector 29, thereby establishing
the electrical connection. On the other hand, the cable-side
connector 104 inserted in the male connector 57 can be detached
from the male connector 57. Contrary to the aforementioned case,
the connector 57 of the connector casing 57a side may be composed
of a female connector and the connector of the cable 103 side may
be composed of a male connector.
[0080] Since the load sensor 51 and the cable 103 to be connected
to the ECU are structured to be detachable from each other by using
a male connector and a female connector, the adaptability of the
load sensor 51 and the connector casing 57a relative to various
kinds of motor vehicles is achieved. The only requirement is
preparing the cable 103 having a length corresponding to the kind
of vehicle. Therefore, the seat load measuring apparatus 10 can be
easily and inexpensively adopted to various kinds of motor
vehicles.
[0081] By utilizing the open bottom of the protector 29, the load
sensor 51 can be effectively protected and the connection and
disconnection between the ECU and the load sensor 51 can be
facilitated. In addition, the seat load measuring apparatus 10 can
be easily and inexpensively adopted to various kinds of motor
vehicles. Moreover, it is not required to form hole(s) and
groove(s) for insertion of the cable-side connector 104, thus
further simplifying the manufacture and reducing the cost.
[0082] Though the connection of the cable-side connector 104 is
achieved by utilizing the open bottom of the protector 29, the
connection of the cable-side connector may be achieved by utilizing
the open top of the protector 29. In this case, the entry of the
sensor-side connector 57 is arranged to face upwardly. Instead of
the protector 29 which is open in at least one side in the vertical
direction of the vehicle, a protector 29 which is open in at least
one side in the longitudinal direction of the vehicle or a
protector 29 which is open in at least one side in the lateral
direction of the vehicle may be employed. Further, a protector 29
which is open in at least one side in the diagonal direction from
upper front to lower back or from lower front to upper back, a
protector 29 which is open in at least one side in the diagonal
direction from upper left to lower right or from lower left to
upper right, or a protector 29 which is open in at least one side
in the diagonal direction from forward left to backward right or
from backward left to forward right may be employed. That is, the
protector 29 of the present invention may be a protector which is
open in at least one side in any of the vertical direction, the
longitudinal direction, the lateral direction, the diagonal
direction from upper front to lower back or from lower front to
upper back, the diagonal direction from upper left to lower right
or from lower left to upper right, and the diagonal direction from
forward left to backward right or from backward left to forward
right. However, it is preferable to utilize the open bottom of the
protector 29 for connection of the cable-side connector 104,
because of the aforementioned reason.
[0083] Of course, the male connector 57 and the cable-side
connector 104 can be delivered in the connected state. In addition,
since the male connector 57 and the cable-side connector 104 are
allowed to be connected during the assembly of a vehicle body by a
car manufacturer, the male connector 57 and the cable-side
connector 104 can be delivered separately. Moreover, the
flexibility during manufacturing process is improved. In this
manner, a seat load measuring apparatus which can be effectively
adapted for various kinds of motor vehicles and has improved
compatibility and efficiency.
[0084] As a seat load is exerted on the sensor plate 52, distortion
corresponding to the seat load is caused on the sensor plate 52 so
that the resistance values of the four strain resistors 105, 106,
107, 108 vary. The variations in the strain resistance value are
detected, outputting a detection signal. The detection signal is
transmitted from the sensor-side connector 57 to the ECU through
the cable 103 (see FIG. 11). The ECU calculates the distortion of
the sensor plate 52, that is, the seat load on the basis of the
detection signal transmitted from the strain resistors. It should
be noted that, instead of the detection of distortion of the sensor
plate 52 by the strain resistors, the load may be obtained by
conversion from deflection of the sensor plate 52 detected by other
elements such as electrical capacitance pressure sensors or Hall
elements.
[0085] The structure of mounting the sensor plate 52 to the base
bottom 22 will be described here. As can be seen clearly in FIG.
5(B), a standing center post 59 is fixed to the base bottom 22 at
the middle in the longitudinal direction of the base bottom 22. The
center post 59 is a substantially cylindrical member having bolts
B1, B2 projecting upwardly and downwardly. The lower bolt B2 of the
center post 59 penetrates the base bottom 22 and is screwed into a
center nut 59N. The upper bolt B1 of the center post 59 penetrates
a central hole 52e (see FIG. 4) of the sensor plate 52 and is fixed
by the center nut 58N via a center washer 59W. The center of the
sensor plate 52 is solidly fixed to the base bottom 22 of the base
frame 21 through the center post 59.
[0086] The structure of the load sensor 51 will be further
described. Attached to the both front and rear ends of the sensor
plate 52 are half arms 53, 55. The half arms 53, 55 are two pairs
to be arranged at front and rear ends of the sensor plate 52,
respectively. As for each pair, the half arms 53, 55 are arranged
above and below the sensor plate 52 to clamp the sensor plate 52 as
shown in FIG. 4 and FIG. 5(B). Since the half arms 53, 55 have same
configuration, a description will be made as only the half arm 55
arranged below the sensor plate 52.
[0087] As shown in FIG. 4, the half arm 55 is a plate member of a
rectangular shape and is provided with a mounting hole 55e formed
in the center of the base thereof. The half arm 55 has wings 55a
which project in the rightward and leftward directions from edges
thereof near the center. Levee-like supports 55b are formed on the
backs of the wings 55a to extend in the rightward and leftward
directions. The top of each support 55b is slightly edged.
[0088] Hereinafter, a description will be made as regard to the
assembly structure of the upper and lower half arms 53, 55, the
sensor plate 52, and the action portions (arm caps 66A) of the Z
arm 61. As can be seen most clearly in FIG. 5(B), the bases of the
upper half arm 53 and the lower half arm 55 fully abut on the
surfaces of the sensor plate 52 and are fixed by bolts 56B and nuts
56N. The wings 53a, 55a of the upper and lower half arms 53, 55 are
arranged in such a manner that the supports 53b, 55b confront each
other. Sandwiched between the supports 53b, 55b are the arm caps
66A of the Z arm action portions. The supports 53b, 55b are
positioned at the necks 52c of the sensor plate 52.
[0089] The actions of the upper and lower half arms 53, 55, the
sensor plate 52, and the Z arm 61 when load is applied to the seat
load measuring apparatus 10 are described in detail, for example,
in Japanese Unexamined Patent Publication No. 2000-258223 and
should be understood by reading the publication, so the description
will be omitted here. The Load applied to the seat load measuring
apparatus 10 is obtained by the computation of the ECU on the basis
of the measured distortion of the sensor plate 52.
[0090] Hereinafter, description will be made as regard to the works
of the mounting portion 40 at the rear end side of the seat load
measuring apparatus 10 having the aforementioned structure. FIGS.
9(A), 9(B) show an example of a rear end portion of a base frame of
a seat load measuring apparatus as a comparative example relative
to the present invention, wherein FIG. 9(A) is a sectional view
showing the normal state and FIG. 9(B) is a sectional view showing
a state after a force in a direction of lifting the seat is
exerted. FIGS. 10(A), 10(B) show the rear end portion of the base
frame of the seat load measuring apparatus according to the
embodiment of the present invention, wherein FIG. 10(A) is a
sectional view showing the normal state and FIG. 10(B) is a
sectional view showing a state after a force in a direction of
lifting the seat is exerted.
[0091] As shown in FIGS. 9(A), 9(B), in a mounting portion 40' of
the seat load measuring apparatus of the comparative example, only
a single stopper bolt, i.e. the front stopper bolt 26, is provided
for transmitting an excessive load exerted on a rear rail bracket
45' to a base frame 21. The stopper bolt 26 is perfectly fitted
relative to the rear rail bracket 45' and a Z arm 61Rr and is
loosely fitted in elongate holes 42 of the base frame 21. A lower
surface of a lower rail 15 and a top portion 46' of the rear rail
bracket 45' are connected to each other by two rivets 15R aligned
in the longitudinal direction. On the other hand, a base bottom 22
of the base frame 21 is connected to a seat bracket (leg) 9' by a
single rivet 9R at a front side (left side in FIGS. 9(A), 9(B)) and
a welded portion W at a rear side. It should be noted that the
welded portion W is more securely welded, for example by continuous
welding, than spot welding of the present invention shown in FIG.
10 as described later.
[0092] The seat bracket 9' is fixed to a vehicle floor 7 by a bolt
7B. The vertical center line between the two upper rivets 15R and
the vertical center line of the stopper bolt 26 are shifted from
each other as shown in the drawings. The seat bracket 9' has two
holes at locations corresponding to two holes 22A formed in the
aforementioned base bottom 22. The holes 22A are provided for
insertion of riveting jig J (shown by a virtual line in FIG. 9(A)).
The riveting jig J is used for driving the rivets 15R for
connecting the rail 15 and the rail bracket 45' after the seat load
measuring apparatus and the seat rail 15 are put on the seat
bracket 9'. Instead of the rivets 15R, bolts and nuts which can be
inserted into the holes 22A may be used to connect the rail 15 and
the rail bracket 45'.
[0093] In the mounting portion 40 of the seat load measuring
apparatus 10 of the embodiment shown in FIGS. 10(A), 10(B), two
stopper bolts, i.e. the front and rear stopper bolts 26, 28, are
provided for transmitting an excessive load exerted on the rear
rail bracket 45 to the base frame 21. The front stopper bolt 26 is
perfectly fitted relative to the rear rail bracket 45 and the Z arm
61Rr and is loosely fitted in the elongate holes 42 of the base
frame 21 (see FIG. 7(A)). On the other hand, the rear stopper bolt
28 is perfectly fitted relative to the base frame 21 and is loosely
fitted in the elongated holes 49 of the rear rail bracket (see also
FIG. 6(A)).
[0094] A lower surface of the lower rail 15 and the top portion 46
of the rear rail bracket 45 are connected to each other by two
rivets 15R aligned in the longitudinal direction. The base bottom
22 of the base frame 21 is connected to the seat bracket 9 by a
single rivet 9R at a front side (left side in FIGS. 10(A), 10(B))
and spot welding portions SP (at two locations aligned in the
lateral direction of the vehicle) at the middle. The seat bracket 9
has two holes at locations corresponding to the holes 22A (see also
FIG. 2) formed in the base bottom 22. Similarly to the above case,
the holes 22A are provided for insertion of a riveting jig. While
the vertical center line between the upper two rivets 15R and the
vertical center line of the front stopper bolt 26 are shifted from
each other, the vertical center line between the rivets 15R is
substantially the same as the vertical center line of the rear
stopper bolt 28. In this example, in the event of generation of an
excessive load, the load applied to the seat rail 15 is transmitted
directly to the seat bracket 9 via the rail bracket 45 and the rear
stopper bolt 28. Therefore, relatively simple structure is enough
for the connection between the base frame 21 of the seat load
measuring apparatus 10 and the seat bracket 9.
[0095] The seat bracket 9 shown in FIGS. 10(A), 10(B) has a fixed
base 9a and connecting portions 9b extending diagonally from the
fixing base 9a. The fixed base 9a is fixed to a vehicle floor 7 by
a bolt 7B. The connecting portions 9b stand along the respective
base side walls 23L and 23R. The connecting portions 9b are
disposed in spaces (see FIG. 2 and FIGS. 6(A), 6(B)) between the
hexagonal head 28H of the rear stopper bolt 28 and the outer
surface of the corresponding base side wall 23L, 23R and between
the bearing surface of the stopper nut 28N and the outer surface of
the corresponding base side wall 23L, 23R. The rear stopper bolt 28
penetrates the centers of the connecting portions 9b.
[0096] When large deceleration is applied to the vehicle body in
the forward direction, for example, in the event of a vehicle
collision, a moment inclining the occupant on the vehicle seat 1
toward the front acts on the vehicle seat 1 so that the rear side
of the vehicle seat 1 is about to go up. As the vehicle seat 1 goes
up, the rear end side of the lower rail 15 is lifted.
[0097] In the case of the mounting portion 40' of the comparative
example, as the rear end side of the lower seat rail 15 is lifted
and the rear rail bracket 45' is thus pulled up, the stopper bolt
26 fitted to the rear rail bracket 45' is also lifted as shown in
FIG. 9(B). Then, the stopper bolt 26 is brought in contact with the
upper edges 42X of the elongate holes 42 of the base side wall 23L,
23R. At this point, an upward force FU is exerted on the seat
bracket 45' along the center line between the front and rear rivets
15R and a downward force FD is exerted on the seat bracket 45'
along the vertical center line of the stopper bolt 26. Since the
center lines are shifted from each other, great moment is applied
to the seat bracket 45'. In this case, a significant large amount
of the forces is exerted on the front rivet 15R. In addition, a
pulling force acts on the upper edges 42X of the elongate holes 42
of the base frame 21 due to the moment. It is therefore preferable
to reinforce the upper edges 42X of the elongate holes 42 of the
base side walls 23L, 23R. It is also required that the rear end of
the base bottom 22 is fixed to the seat bracket 9' by relatively
strong welded portion W.
[0098] On the other hand, in the case of the mounting portion 40 of
the embodiment shown in FIGS. 10(A), 10(B) according to the present
invention, as the rear end side of the lower seat rail 15 is lifted
and the rear rail bracket 45 is thus pulled up, the rear stopper
bolt 28 loosely fitted to the rear rail bracket 45 is brought in
contact with the lower edges 49X of the elongate holes 49 as shown
in FIG. 10(B). As a result, the lifting of the rear rail bracket 45
is locked so that reduced load is applied to the front stopper bolt
26 fitted to the rear rail bracket 45. Therefore, the force lifting
up the rear rail bracket 45 is transmitted directly to the
connecting portions 9b of the seat bracket 9 which the rear stopper
bolt 28 penetrates. Accordingly, the strength provided by the spot
welding portions SP is enough for fixing the base frame 21 to the
seat bracket 9 at the rear side.
[0099] As shown in FIG. 10(B), the moment of inclining the seat is
applied evenly to the two rivets 15R connecting the lower rail 15
and the rear rail bracket 45 so as to reduce the local load on the
lower rail 15 and the rear rail bracket 45, thereby preventing the
lower rail 15 and the rear rail bracket 45 from being deformed.
Since the vertical center line between the upper two rivets 15R is
substantially the same as the vertical center line of the rear
stopper bolt 28 as described above, the force of breaking the
rivets 15R and the moment of bending the lower rail 15 are reduced.
The moment of inclining the lower rail 15 is transmitted to the
seat bracket 9 via the rear stopper bolt 28 and is finally received
by the vehicle floor 7. The load to the base frame 21 is reduced so
as to restrain the base frame 21 from being deformed. In this
manner, effect of the rising of the seat rear portion upon the
mounting portion 40 is avoided.
[0100] FIGS. 16(A)-16(D) show a variation example of the rear end
portion of the base frame of the seat load measuring apparatus
shown in FIGS. 10(A), 10(B), wherein FIG. 16(A) is a side sectional
view showing the normal state, FIG. 16(B) is a sectional view taken
along a line XVIB-XVIB of FIG. 16(A), FIG. 16(C) is a side
sectional view showing a state after a force in a direction of
lifting the seat is exerted, and FIG. 16(D) is a sectional view
taken along a line XVID-XVID of FIG. 16(C). As the same components
as those of the aforementioned embodiment are marked with the same
numerals, detail description about the components will be
omitted.
[0101] The embodiment shown in FIGS. 10(A), 10(B) is structured
such that, when a large load acts on the vehicle seat in the
lifting direction, for example, in the event of a vehicle
collision, the load is received by the two bolts, i.e. the first
and second stopper bolts 26, 28. On the other hand, this variation
example is structured such that the load is received by only one
bolt, i.e. the second stopper bolt 28 as shown in FIGS. 16(A),
16(B).
[0102] In the variation example, the second stopper bolt 28 is
positioned on the center line between the front and rear rivets 15R
and 15R for fastening the rear rail bracket 45 and the lower rail
15 and is perfectly fitted relative to the base frame 21. Further,
the second stopper bolt 28 is loosely fitted in the elongate holes
49 of the rear rail bracket 45 and also loosely fitted in circular
holes 9c formed in the both side walls of the seat bracket 9.
[0103] As a large force acts on the vehicle seat in the rising
direction as mentioned above, as shown in FIGS. 16(C), 16(D), the
lower rail 15 and the rear rail bracket 45 are slightly moved
upwardly so that lower peripheral edges of the elongated holes 49
of the rear rail bracket 45 come in contact with the second stopper
bolt 28. After that, the second stopper bolt 28 and the base frame
21 are also slightly moved upwardly. The second stopper bolt 28
comes in contact with upper peripheral edges of the circular holes
9c of the seat bracket 9 and thus pushes up the seat bracket 9.
[0104] In this manner, the large force acting on the vehicle seat
is spread to be received by both the seat bracket 9 and the base
frame 21. Therefore, the load acting on the base frame 21 is
reduced.
[0105] Since the force acting on the vehicle seat is received only
by the second stopper bolt 28, the first stopper bolt 26 can be
omitted, that is, reducing the number of parts. Further, since the
first stopper bolt 26 can be omitted, the configuration of the rear
rail bracket 45 can be simplified such that it can be symmetrical
about the position where the second stopper bolt 28 penetrates.
Furthermore, since the second stopper bolt 28 is arranged at a
position on the center line between the first and rear rivets 15R,
15R, no or little offset load or moment due to the offset load is
exerted on the rear rail bracket 45. Therefore, since the load is
applied nearly evenly to the front and rear rivets 15R, 15R, same
rivets can be used for the front and rear rivets 15R, 15R, thus
achieving the adaptability of parts. The other structure and other
works and effects of the variation example are the same as those of
the aforementioned embodiment.
[0106] FIGS. 17(A)-17(D) show another variation example of the rear
end portion of the base frame of the seat load measuring apparatus
shown in FIGS. 10(A), 10(B), wherein FIG. 17(A) is a side sectional
view showing the normal state, FIG. 17(B) is a sectional view taken
along al line XVIIB-XVIIB of FIG. 17(A), FIG. 17(C) is a side
sectional view showing a state after a force in a direction of
lifting the seat is exerted, and FIG. 17(D) is a sectional view
taken along a line XVIID-XVIID of FIG. 17(C). As the same
components as those of the aforementioned examples are marked with
the same numerals, detail description about the components will be
omitted.
[0107] The embodiment shown in FIGS. 16(A) through 16(D) is
structured such that the base frame 21 is fixed to the vehicle
floor 7 via the seat bracket 9 and the rear rail bracket 45 is
fixed to the lower rail 15. On the other hand, this variation
example is structured such that the base frame 21 is fixed to the
lower rail 15 via the seat bracket 9 and the rear rail bracket 45
is fixed to the vehicle floor 7 as shown in FIGS. 17(A) through
17(D). The other structure and other works and effects of the
variation example are substantially the same as those of the
aforementioned example shown in FIGS. 16(A)-16(D).
[0108] FIG. 18 is an exploded perspective view similar to FIG. 4,
but showing a variation example of the sensor portion shown in FIG.
4. As the same components as those of the aforementioned embodiment
are marked with the same numerals, detail description about the
components will be omitted. In the aforementioned sensor plate of
the embodiment shown in FIG. 4, the hole of the washer 58W, the
center hole 52e of the sensor plate 52, and the hole of the center
washer 59W are each formed in a rectangular shape. In this
variation example, however, the hole 58W.sub.1 of the washer 58W,
the center hole 52e of the sensor plate 52, and the hole 59W.sub.1
of the center washer 59W are each formed in a circular shape as
shown in FIG. 18. By forming the holes 58W.sub.1, 52e, 59W.sub.1
into circular shape, the contact areas of the center washer 58W,
the sensor plate 52, and the center washer 59W relative to the bolt
B1 of the center post 59 when fitted are increased. Therefore, when
the center nut 58N is screwed to fasten the bolt B1, the
deformation of the center washer 58W, the sensor plate 52, and the
center washer 59W can be prevented, thereby improving the
stability. The other structure and other works and effects of the
variation example are substantially the same as those of the
aforementioned example.
[0109] FIGS. 19(A), 19(B) show a variation example of the sensor
portion of the seat load measuring apparatus, wherein FIG. 19(A) is
a partial plan view similar to FIG. 12 and FIG. 19(B) is a
sectional view similar to FIG. 13, taken along a line XIXB-XIXB of
FIG. 19(A). As the same components as those of the aforementioned
example are marked with the same numerals, detail description about
the components will be omitted. In the sensor portion of the
aforementioned example shown in FIG. 12 and FIG. 13, the mounting
structure of the sensor plate 52 relative to the base frame 21 are
different from the mounting structure composed of the components
shown in FIG. 4. In this variation example, however, the mounting
structure of the sensor plate 52 relative to the base frame 21 is
the same as the mounting structure composed of the components shown
in FIG. 4, as shown in FIGS. 19(A), 19(B). The other structure and
other works and effects of the variation example are substantially
the same as those of the aforementioned example.
[0110] After the Z arm 61 and the front stopper bolt 26 are
assembled in the base frame 21, the seat load measuring apparatus
10 and the lower rail 15 or the seat bracket 9 are riveted
together. During this, the front stopper bolt 26 and the Z arm do
not interfere the riveting work because the positions of the rivets
are shifted from the front stopper bolt 26 and the front and rear
ends of the Z arm 61.
[0111] As apparent from the aforementioned description, in a seat
load measuring apparatus according to an exemplary embodiment of
the invention, a cable for connecting a load sensor and a control
unit can be designed to be detachable by employing a sensor-side
connector and a cable-side connector, thereby achieving the
adaptability of the load sensor and the connector casing relative
to various kinds of motor vehicles. Only required is preparing a
cable having a length corresponding to the kind of motor vehicle.
Therefore, the seat load measuring apparatus can be easily and
inexpensively adopted to various kinds of motor vehicles.
[0112] According to one embodiment of the present invention, by
utilizing an opening of a protector which is formed in at least one
side in any of the vertical direction, the longitudinal direction,
the lateral direction, the diagonal direction from upper front to
lower back or from lower front to upper back, the diagonal
direction from upper left to lower right or from lower left to
upper right, and the diagonal direction from forward left to
backward right or from backward left to forward right, the load
sensor can be effectively protected and the connection and
disconnection between the load sensor and the cable can be
facilitated. In addition, the seat load measuring apparatus can be
easily and inexpensively adopted to various kinds of motor
vehicles. Moreover, it is not required to form hole(s) and
groove(s) for insertion of the cable-side connector, thus further
simplifying the manufacture and reducing the cost.
[0113] Of course, the sensor-side connector and the cable-side
connector can be delivered in the connected state. In addition,
since the connectors are allowed to be connected during the
assembly of a vehicle body by a car manufacturer, the connectors
can be delivered separately. Moreover, the flexibility during
manufacturing process is improved. In this manner, a seat load
measuring apparatus which can be effectively adopted in various
kinds of motor vehicles and is easier to install, maintain and
manufacture can be provided.
[0114] Furthermore, according to one embodiment of the present
invention the protector is formed just by bending a band-like
plate. Therefore, the protector can be easily and inexpensively
formed. Furthermore, according to one embodiment of the present
invention, a protective mechanism is provided so as to withstand
large load exerted on the mounting portion of the seat load
measuring apparatus disposed between a vehicle seat and a vehicle
floor by a moment in a direction of lifting the rear portion of the
vehicle seat. In addition, the seat load measuring apparatus can be
easily and inexpensively adopted to various kinds of motor
vehicles.
[0115] The priority applications, Japanese Patent Application Nos.
2002-240096 filed on Aug. 21, 2002 and 2002-324758 filed on Nov. 8,
2002 are hereby incorporated by reference herein in their
entireties.
[0116] Given the disclosure of the present invention, one versed in
the art would appreciate that there may be other embodiments and
modifications within the scope and spirit of the invention.
Accordingly, all modifications attainable by one versed in the art
from the present disclosure within the scope and spirit of the
present invention are to be included as further embodiments of the
present invention. The scope of the present invention is to be
defined as set forth in the following claims.
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