Seat position-sensing system

An occupant support for a vehicle includes a vehicle seat and a foundation. The vehicle seat is configured to support an occupant of the vehicle above a floor of the vehicle. The foundation is configured to interconnect the vehicle seat to the floor to permit movement of the vehicle seat relative to the floor along a linear path.

BACKGROUND

The present disclosure relates to a vehicle seat, and particularly to a seat-position sensing system within a vehicle seat. More particularly, the present disclosure relates to a seat-position sensing system used to determine a position of the vehicle seat.

SUMMARY

According to the present disclosure, an occupant support for a vehicle includes a vehicle seat and a foundation. The vehicle seat is configured to support an occupant of the vehicle above a floor of the vehicle. The foundation is configured to interconnect the vehicle seat to the floor to permit movement of the vehicle seat relative to the floor along a linear path.

In illustrative embodiments, the occupant support includes a vehicle seat position-sensing system adapted to determine the position of the vehicle seat along the floor. The vehicle seat position-sensing system includes an input wheel, a rotation translator, and a sensor. The input wheel is configured to rotate as the vehicle seat moves relative to the floor. The translator is configured to provide means for translating an input rotational speed provided by the input wheel to a relatively slower output rotational speed to cause about one output rotation to occur in response to traveling from a beginning to an end of the linear path. The sensor is couple to an output of the translator and configured to sense a rotational position of the output of the translator so that a linear position along the liner path may be determined.

In illustrative embodiments, the translator includes a housing, an output shaft, an inner torsion spring, and an outer torsion spring. The inner torsion spring is coupled on one end to the input wheel and coupled on an opposite end to the output shaft. The outer torsion spring is coupled on one end to the housing and coupled on an opposite end to the output shaft. In use, the input wheel rolls along a stationary portion of the foundation as the vehicle seat moves along the linear path. As a result, the outer torsion spring unwinds and the inner torsion spring winds at the same time. The difference in rated the unwinding and winding causes output shaft to rotate at a different rotational speed than the input wheel.

DETAILED DESCRIPTION

An occupant support10configured for use in a passenger vehicle is shown inFIG. 1. Occupant support10includes a vehicle seat4, a foundation14, and a vehicle seat position-sensing system16. Vehicle seat4is configured to support an occupant of the vehicle about floor15of the vehicle. Foundation14is configured to interconnect vehicle seat4to floor15to permit movement of vehicle seat4relative to floor15along a predetermined linear path. When the occupant is supported by vehicle seat4, movement of vehicle seat4relative to floor15along path P adjusts the position of the occupant relative to floor15and vehicle seat position-sensing system16determines the location of vehicle seat4along floor15.

When an occupant is supported by vehicle seat4, movement of vehicle seat4relative to the floor15along longitudinal path P adjusts the position of the occupant relative to the floor15. Vehicle seat position-sensing system16determines the absolute location of the vehicle seat4along the floor15. Vehicle seat position-sensing system16is couple to an upper track24which slides along a stationary track26(also called lower track26) which is fixed to the vehicle floor15.

Vehicle seat position-sensing system16includes an input wheel12, a sensor2, and a rotation translator18as shown inFIGS. 1-3. Input wheel12is configured to rotate as the vehicle seat4moves relative to the floor15. Rotation translator18is configured to provide means for translating an input rotational speed of the input wheel12to a relatively slower output rotational speed to cause about one output rotation to occur in response to traveling from a beginning to an end of the predetermined linear path P. Sensor2is coupled to an output of the rotation translator and configured to sense a rotational position of the output of the translator so that a linear position along the liner path may be determined.

Rotation translator18includes a housing5, an output shaft7, an inner spring6and an outer spring8. Housing5is coupled to a movable component24of foundation14in a fixed position relative to movable component24. Output shaft7is coupled to sensor2to rotate therewith. Inner spring6is coupled on one end to input wheel12and coupled on an opposite end to output shaft7. Outer spring8is coupled on one end to housing5and coupled on an opposite end to output shaft7.

In an illustrative example, inner spring6has a first spring constant and outer spring8has a second spring constant. In one example, the first spring constant is different than the second spring constant. In another example, the first spring constant is greater than the second spring constant.

Outer torsion spring8is arranged to extend along and around output shaft7. Inner torsion spring6is arranged to extend along and around output shaft7. Inner torsion spring6is located between outer torsion spring8and output shaft7.

In one example, sensor2is an accelerometer. However, any other suitable sensor may be used. Reference is hereby made to U.S. Patent Publication No. US2016/0101710, filed Oct. 8, 2015, published Apr. 14, 2016, and entitled SEAT POSITION SENSING AND ADJUSTMENT for disclosure relating to accelerometers in vehicle seats, which application is hereby incorporated in its entirety herein.

Controller20is coupled to sensor2, and controller20includes memory21and processor22. Memory21has instructions stored therein that are executable by processor22to cause controller20to receive the signal from sensor2and determine the location of vehicle seat4along linear path P based on the signal from sensor2.

The outer torsion spring8has a different spring rate that inner torsion spring6that opposes the winding proportionally to the spring rate differential. The result is a reduction in angular velocity of output shaft7as opposed to the input wheel12. In one example, the input wheel12rotates approximately four rotations and the output shaft7with the accelerometer2rotates less than 360 degrees. In another example, for every ten rotations of input wheel12, output shaft7rotates about once. In one example, a reduction ratio is the ratio of input wheel12rotations to output shaft7rotations. Any suitable reduction ratio may be used. The reduction ratio may be based on a length of the predetermined path P, diameter of input wheel12, diameter of output shaft7, sensitivity of sensor2, and any other suitable factor.

As suggested inFIG. 6, C is assumed to be a reduction ratio, x as an input and the θias an output. The reduction ratio C may be calculated according the following mathematical equations:

J→Second polar moment of inertia

G→Flexural modulus of the shaft

L→Distance between springs

ki,ko→Inner an outer Spring Constant, respectively

θi,θo→Rotation of inner and outer spring, respectively

The input wheel12rolls along the stationary track26. As a result, the two counter wound torsion springs6,8react upon each other causing the output shaft7with the accelerometer2to rotate at slower rate than the input wheel12.

An occupant support for a vehicle, the occupant support comprising a translator, an inner torsion spring, an input transmission mechanism, an output shaft, an outer torsion spring, and a vehicle seat that moves along a linear path relative to a floor of the vehicle, wherein one of the torsion springs unwinds in a first direction and the other of the torsion springs winds in a second direction, the second direction being different relative to the first direction, in which winding and unwinding occurs simultaneously for both springs, in which the difference in the rate of unwinding and winding causes the output shaft to rotate at a different rotational speed than the input transmission mechanism.

In one example, the translator may include the output shaft, the inner torsion spring, and the outer torsion spring located in a space formed in a single housing.

In one example, at least one of the outer torsion spring and the inner torsion spring is coupled on one end to an input mechanism and coupled on an opposite end to the output shaft. At least one of the outer torsion spring and the inner torsion spring is adapted to wind in a first clockwise direction.

In one example, the outer torsion spring is coupled on one end to the housing and coupled on an opposite end to the output shaft. The outer torsion spring is adapted to unwind in a second counter-clockwise direction.

In one example, the other of the at least one of the outer torsion spring and the inner torsion spring is coupled on one end to the housing and coupled on an opposite end of the output shaft.

In one example, the input mechanism translates along a stationary portion of the floor of the vehicle as the vehicle moves along the linear path. In one example, the input mechanism is an input wheel. In another example, the input mechanism is a non-circular frame or disk arranged to revolve on an eccentric axis. In another example, the input mechanism is a semi-circular frame or disk arranged to revolve on a circumcentral axis. In another example, the input mechanism is a semi-circular frame or disk arranged to revolve on an eccentric axis.