Chairs and seats – Movable bottom – Bottom and back movable as a unit
Reexamination Certificate
2001-12-13
2003-12-23
Nelson, Jr., Milton (Department: 3636)
Chairs and seats
Movable bottom
Bottom and back movable as a unit
Reexamination Certificate
active
06666513
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a vehicle seat drive having a mechanical inchworm linear motion actuator for driving a vehicle seat.
2. Background Art
Vehicle seat drives provide at least six degrees of automated motion. These degrees of motion include fore and aft, up and down, and forward and backward tilting. Typical vehicle seat drives use three separate DC permanent magnet motors that drive ball screws via extensive gearing to accomplish these degrees of motion. Typical vehicle seat drives are heavy and large and take up substantial foot space beneath a vehicle seat. What is needed is a lighter, less complex, and more compact vehicle seat drive which requires fewer components, is relatively cheap to manufacture, and is relatively noiseless during operation. Such a vehicle seat drive would incorporate a mechanical inchworm linear motion actuator.
Existing inchworm linear motion actuators include piezoelectric and magnetostrictive linear actuators. Piezoelectricity is the property by which a material reacts to an applied electric voltage by changing shape and, vice versa, generating an electric current in response to an applied mechanical stress. Piezoelectrics transfer electrical energy into mechanical energy and transfer mechanical energy into electrical energy. Piezoelectrics are often used in precision positioning devices as both actuators and sensors. Piezoelectrics respond only with microscopic dimensional changes, but when multi-layered, macroscopic motions can be produced.
Used in linear and rotary actuators, piezoelectrics allow for simple, highly dynamic designs that can achieve high force density and provide noiseless operation and high holding forces. However, the disadvantages of piezoelectrics include their high cost and undesirable material properties such as hysteresis creep, brittleness, and temperature sensitivity.
In the design of piezoelectric linear actuators, piezoelectric stacks are arranged to produce inchworm motion by alternating clamping and translation. The basic concept behind a piezoelectric inchworm linear motion system
10
is illustrated in FIG.
1
A through FIG.
1
H. System
10
includes a central piezoelectric actuator
12
, left and right clamping piezoelectric actuators
14
a
and
14
b
, and a shaft
16
. Central actuator
12
performs a length changing function and clamping actuators
14
a
and
14
b
perform a clamping function.
In
FIG. 1A
, system
10
is off and each of actuators
12
,
14
a
, and
14
b
, are opened and disengaged from shaft
16
. In
FIG. 1B
, left clamping actuator
14
a
closes and clamps onto shaft
16
. This is a representation of the clamping function. In
FIG. 1C
, central actuator
12
compresses towards shaft
16
and extends thereby moving left clamping actuator
14
a
with the shaft in the left direction. This is a representation of the length changing function. In
FIG. 1D
, right clamping actuator
14
b
closes and clamps onto shaft. In
FIG. 1E
, left clamping actuator
14
a
opens and disengages shaft
16
. In
FIG. 1F
, central actuator
12
contracts and shaft
16
moves further in the left direction. In
FIG. 1G
, left clamping actuator
14
a
closes and clamps onto shaft
16
. In
FIG. 1H
, the process starts to repeat with right clamping actuator
14
b
opening and disengaging shaft
16
.
System
10
has a very simple design that uses only piezoelectric actuation. Depending upon the electrical input sequence, shaft
16
may be moved in either direction at variable speeds. However, in addition to the other disadvantages noted above, the lack of a self locking state (in the absence of power) is undesirable.
Magnetostriction inchworm linear motion systems use magnetic fields to move special types of metal having magnetostrictive properties. Magnetostriction is the phenomenon in which magnetic energy is transferred into mechanical energy and vice versa. In the first case, known as the Joule effect, magnetostrictive materials change shape in response to a changing magnetic field. The Joule effect is used mainly in actuators where motion or force is the desired outcome. As most devices couple electric and magnetic energy (for example, using electric current with changing magnetic field), magnetostrictive motion systems are really electromagneto-mechanical devices.
The basic physical operation of magnetostriction is as follows. When no magnetic field is applied the domains that make up the molecular structure of magnetostrictive materials are disorganized. Upon exposure to a magnetic field, the domains rotate and align with the magnetic field. The reorientation of the molecular domains causes geometric distortion on the macroscopic level thereby elongating the material along the direction of the magnetic field. As the magnetic field gets stronger, more domains get aligned and greater elongation is achieved.
The main components of a magnetostriction inchworm linear motion system include a magnetostrictive rod and a metal cylindrical housing around which induction coils are wound. The rod inches up and down by stretching and pushing against the sides of the housing. The limiting factor for use of magnetostrictive alloys is cost as these alloys are made from expensive rare earth elements. Accordingly, magnetostriction inchworm linear motion systems are uneconomical to incorporate in the mass assembly of vehicles.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a vehicle seat drive having a mechanical inchworm linear motion actuator for driving a vehicle seat.
It is another object of the present invention to provide a vehicle seat drive having an actuation module and a jamming module for performing length changing and clamping functions to drive a vehicle seat.
It is a further object of the present invention to provide a vehicle seat assembly having a vehicle seat drive including a mechanical inchworm linear motion actuator.
In carrying out the above objects and the other objects, the present invention provides a vehicle seat drive having a linearly movable shaft coupled to the vehicle seat such that the vehicle seat moves as the shaft moves. The vehicle seat drive further includes a jamming module having left and right jamming plates operable for engaging and disengaging the shaft while moving linearly with respect to the shaft. The vehicle seat drive also includes an actuation module operable for applying linear forces on the jamming plates to have the jamming plates engage and disengage the shaft and move linearly with respect to the shaft. The actuation module applies a first linear force in the left direction on the left jamming plate to have the left jamming plate engage and move the shaft in the left direction thereby moving the vehicle seat to the left.
Further, in carrying out the above objects and other objects, the present invention provides a vehicle seat assembly having a vehicle seat and a linearly movable shaft coupled to the vehicle seat such that the vehicle seat moves as the shaft moves. The vehicle seat assembly further includes a jamming module having left and right jamming plates operable for engaging and disengaging the shaft while moving linearly with respect to the shaft. The vehicle seat assembly also includes an actuation module operable for applying linear forces on the jamming plates to have the jamming plates engage and disengage the shaft and move linearly with respect to the shaft. The actuation module applies a first linear force in a first linear direction on one of the jamming plates to have the one of the jamming plates engage and move the shaft in the first linear direction thereby moving the vehicle seat in the first linear direction.
Also, in carrying out the above objects and other objects, the present invention provides a vehicle seat drive for driving a vehicle seat between fore and aft positions. The vehicle seat drive includes an actuation module having a motor, a rotatable shaft, and a wobble plate. The motor is coupled to the rotatable shaft to rotatably drive the rotatable sha
Blanco Ernesto E.
Massery Luke
Maue H. Winston
Pheiffer Rory Patrick
Sandoval Daniel
Jr. Milton Nelson
Lear Corporation
Panagos Bill C.
LandOfFree
Vehicle seat drive having a mechanical inchworm linear... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Vehicle seat drive having a mechanical inchworm linear..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Vehicle seat drive having a mechanical inchworm linear... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3175133