1. A differential gear mechanism for a vehicle, comprising:
a housing driven to rotate about a rotational axis and including contact surfaces;
first and second sun gears provided within the housing to be rotatable about the rotational axis, each of the first and second sun gears including an external gear portion at an outer periphery;
first and second planetary gears rotatably provided within the housing and engaging with the external gear portions of the sun gears respectively, the planetary gears engaging with each other;
the first and second sun gears including axial end surfaces respectively pressed against the contact surfaces of the housing by the first and second sun gears being pressed along the rotational axis by means of thrust forces generated at engagement surfaces between the external gear portions of the first and second sun gears and the first and second planetary gears respectively; and
each of the first and second sun gears including a first portion having the external gear portion, a second portion formed separately from the first portion, and a thrust force generating mechanism formed between the first portion and the second portion for generating thrust forces at the first portion and the second portion in a direction parallel with the rotational axis when a power transmission is performed between the first portion and the second portion, wherein a direction of the thrust force generated at the first portion by the thrust force generating mechanism is specified to be equal to a direction of the thrust force generated at the first portion by means of the engagement between each of the external gear portions and each of the first and second planetary gears.
2. A differential gear mechanism according to claim 1, wherein the external gear portions and the first and second planetary gears include helical teeth respectively and the first and second plant gears are arranged in parallel with the rotational axis.
3. A differential gear mechanism according to claim 2, wherein each of the thrust force generating mechanisms includes a spline bore formed at an inner periphery of the first portion and including helical teeth and a spline portion formed at an outer periphery of the second portion and engaging with the spline bore of the first portion, the first portion forming a cylindrical shape.
4. A differential gear mechanism according to claim 3, wherein an outer diameter of the spline portion of one of the first and second sun gears is different from an outer diameter of the spline portion of the other one of the first and second sun gears.
5. A differential gear mechanism according to claim 3, wherein a helical angle of the spline portion of one of the first and second sun gears is different from a helical angle of the spline portion of the other one of the first and second sun gears.
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. A safety roman blind comprising:
a headrail extending in a longitudinal direction;
a blind curtain having an upper end portion which is connected to said headrail, and extendable in an upright direction transverse to the longitudinal direction to terminate at a lower end portion, said blind curtain being configured to have a plurality of fold regions which are displaced from each other in the upright direction by a plurality of droopable regions such that when said lower end portion is lifted to a raised position, said droopable regions are brought into a stacked arrangement with each other in a transverse direction that is transverse to the longitudinal and upright directions, each of said fold regions having a plurality of attached spots which are displaced from each other along a folded line;
at least one lift cord having a pulled cord segment which is disposed rearwardly of a rear major surface of said blind curtain, and which has a terminal end that is secured to a lowermost one of said fold regions, said pulled cord segment being suspended from said headrail and liftable along a lifting path in the upright direction such that said terminal end is displaceable to the raised position by a lifting force applied to said lift cord; and
a shielding web unit having a web sheet which is extendable in the upright direction, and which has a plurality of attachment regions that are displaced from each other in the upright direction, each of said attachment regions having a plurality of attaching spots which are displaced from each other along an attachment line and which are in mated attachments to said attached spots of a corresponding one of said fold regions to bring the attachment and fold lines in line with each other, said attaching and attached spots being offset from the lifting path, said web sheet being made from a web material thinner and lighter than that of said blind curtain such that, when said lower end portion is lifted to the raised position, said web sheet is bent away from said fold regions so as not to be trapped in between said droopable regions, thereby preventing lifting movement of said pulled cord segment along the lifting path from being obstructed.
2. The safety roman blind as claimed in claim 1, wherein said shielding web unit has at least one casing which defines a channel extending along the lifting path to receive said pulled cord segment therein, and which is attached to said web sheet along the lifting path and between two adjacent ones of said attaching spots of each of said attachment regions.
3. The safety roman blind as claimed in claim 2, wherein said shielding web unit is made from a netting material, said casing being integrally formed with said web sheet by stitching.
4. The safety roman blind as claimed in claim 3, wherein said blind curtain has a plurality of weighting rods disposed on said fold and droopable regions, respectively.
5. The safety roman blind as claimed in claim 3, wherein said casing is attached to a rear major surface of said web sheet distal from said blind curtain.
6. The safety roman blind as claimed in claim 3, wherein said casing is attached to a front major surface of said web sheet proximate to said blind curtain.