1. A seat belt retractor comprising:
a spool on which a seat belt is taken up; a motor that generates a driving torque for rotating the spool; and a power transmission mechanism that transmits the driving torque of the motor to the spool via a planetary gear mechanism, the seat belt retractor being configured to take up the seat belt on the spool by using the driving torque of the motor,
wherein the planetary gear mechanism includes a sun gear to which the driving torque of the motor is transmitted, a rotatable internal gear member including inner teeth formed along an inner circumferential surface and ratchet teeth formed along an outer circumferential surface, a predetermined number of planet gears each meshed with both of the sun gear and the inner teeth of the internal gear member, and a carrier that rotatably supports the predetermined number of planet gears and transmits the driving torque of the motor to the spool.
the power transmission mechanism includes a clutch pawl set to move between a non-operating position where the clutch pawl is disengaged from the ratchet teeth of the internal gear member thereby allowing the internal gear member to rotate thus disconnecting a power transmission route and an operating position where the clutch pawl is engaged with one of the ratchet teeth of the internal gear member thereby inhibiting the internal gear member from rotating thus connecting the power transmission route,
the internal gear member is formed of a noise suppressing material that suppresses noise generated when the planetary gear mechanism is operating, and
the seat belt retractor further includes a deformation restricting portion that restricts deformation of the internal gear member.
2. The seat belt retractor according to claim 1,
wherein the deformation restricting portion is provided on the carrier.
3. The seat belt retractor according to claim 2,
wherein the carrier includes an annular portion, and
the deformation restricting portion is formed in an annular shape along the annular portion of the carrier so as to restrict deformation of the internal gear member when the internal gear member about to be deformed makes contact with the deformation restricting portion.
4. The seat belt retractor according to claim 3,
wherein the annular deformation restricting portion is continuously formed along the entire circumference of the annular shape thereof, or discontinuously formed along the circumference of the annular shape thereof in predetermined regions of the carrier opposing the respective planet gears.
5. The seat belt retractor according to claim 4,
wherein the annular deformation restricting portion is formed as an annular flange or an annular projection.
6. The seat belt retractor according to claim 1,
wherein the noise suppressing material is a synthetic resin.
7. A seat belt unit comprising:
a seat belt that binds an occupant; a seat belt retractor that retracts the seat belt; a tongue slidably supported by the seat belt; and a buckle with which the tongue is engaged upon being inserted therein, the seat belt being arranged to be fitted on the occupant when the tongue is engaged with the buckle upon being inserted therein,
wherein the seat belt retractor is the seat belt retractor according to claim 1.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. Method for controlling a matrix display screen with lines (li) and columns (cj) that intersect to form an image point (Pi,j), including application of a line selection voltage (VLS) to a line during a line selection time (Tls), and simultaneously a voltage corresponding to a grey level (G) to be displayed at the associated image point to a column, characterised in that the said grey level is chosen from among 2q levels and is numerically coded according to a non-linear law in accordance with the brightness perception of a human eye, the different voltages (Vci, Vci+1) to be applied to the columns are chosen in a strictly increasing series of (2n+1) voltages where n is an integer \u22671, these voltages being distributed in N=2n pairs of consecutive voltages, each pair being used to display a range of grey levels and in that the line selection time (Tls) is subdivided into one or several groups of 2(q-n) time intervals where (q-n) is an integer >1, each group having the same duration, the distribution of these 2(q-n) time intervals into a group for a pair of voltages, being done according to a non-linear law with a transfer function close to the inverse of the transfer function previously used to code the grey levels for the corresponding grey levels range, the voltage applied to a column for a pair of voltages and a group of time intervals being determined either using one of the values of the pair of voltages throughout the duration of the group, or switching from one value of the pair of voltages to the other, at least once during the duration of the group at the end of a time interval.
2. Method according to claim 1, characterised in that the coding law of a grey level G is such that:
G=(2q\u22121)\xd74.5\xd7PG
for PG\u226750.018 and
G=(1.099\xd7PG)0.45\u22120..099(2q\u22121)
for PG>0.018, where PG is a relative weight assigned to the grey level.
3. Method according to claim 2, characterised in that for a given pair of voltages, a given range of grey levels, a given group of time intervals and a given grey level to be displayed, the voltage of the pair leading to the highest brightness is applied for a time interval given by:
\u0394t=\u03c4 (PG\u2212PGinf)(PGsup\u2212PGinf) where \u03c4 is the duration of a group of 2q-n time intervals, PG is the weight of the grey level to be displayed, PGsup and PGinf are the weights of the grey levels corresponding to the upper and lower limits respectively of the range of grey levels associated with the pair of voltages.
4. Method according to claim 1, characterised in that when the line selection time is subdivided into two groups of time intervals, the time intervals in the two groups are distributed symmetrically about the middle of the line selection time.
5. Method according to claim 1, characterised in that during the line selection time, the line selection line is free of voltage transients.
6. Method according to claim 1, characterised in that the display screen is a flat panel with electron source.
7. Control device for a matrix display screen according to the method in claims 1 to 6, characterised in that it comprises:
a numeric data source (20) capable of supplying binary words coded on q bits according to the non-linear law in accordance with the brightness perception by a human eye and representing the codes for 2q grey levels to be displayed,
a screen controller (21) receiving synchronisation signals from the data source (20) and managing signals capable of driving a line sweep generator (22) and a column driving voltage generator (23) that receives codes of the grey levels to be displayed for each column, and that is used to generate the voltages of the voltage pairs and if necessary to switch from one voltage in a pair to the other, using a discrete voltage generator (24) and in that
the binary words are subdivided into two sub-words, one with n bits corresponding to the high order bits and the other with q-n bits corresponding to low order bits, the column driving voltage generator (23) comprising a combinational logic stage (15) controlling a set (16) of analogue switches (CA) to pre-select a pair of voltages output by the discrete voltage generator (24) from the n high order bits of a binary word and a signal output by a counter (13) initialised at each line selection time and to switch from one of the voltages in the pair to the other when the counter (13) has reached the value corresponding to the q-n low order bits of the binary word.
8. Control device according to claim 7, characterised in that the counter (13) receives a set of non-linearly distributed pulses corresponding to the pair of voltages output from a pulse generator (11) connected to the screen controller through a multiplexer (12) also receiving the n high order bits of the binary word output by the data source (20) as an address.
9. Control device according to claim 7, characterised in that the combinational logic stage (15) receives the n high order bits of the binary word output by the data source (20) through an offset register associated with memory flip-flops (10).
10. Control device according to claim 7, characterised in that the combinational logic stage (15) is connected to the counter (13) through a comparator (14) that makes a comparison between the signal output from the counter (13) and the q-n low order bits of the binary word output by the data source (20).