1. A piston ring assembly, comprising:
an upper ring;
a lower ring;
wherein a first portion of said upper ring is in contact with a corresponding first portion of said lower ring; and
an expander positioned between corresponding second portions of said upper ring and said lower ring, said expander including apexes adapted to contact said second portions of said upper and lower rings;
wherein radial compression of said upper and lower rings induces axial expansion of said expander.
2. A piston ring assembly according to claim 1, wherein upon positioning the piston ring assembly within a ring groove of a piston, said axial expansion of said expander urges said upper ring against an upper surface of said ring groove and said lower ring against a lower surface of said ring groove.
3. A piston ring assembly according to claim 1, wherein said upper ring includes a first shoulder recess about an inner periphery thereof and said lower ring includes a second shoulder recess about an inner periphery thereof, said first and second shoulder recesses defining a cavity to receive said expander.
4. A piston ring assembly according to claim 1, wherein said expander is generally sinusoidal in shape and includes two ends defining an expander gap such that radial compression of said upper and lower rings mates said two ends thereby closing said expander gap and said mated two ends form a generally W-shaped configuration.
5. A piston ring assembly according to claim 1, wherein said apexes of said expander are generally flat and are supported by two adjacent leg members such that an angle defined by said adjacent leg members is about 16 degrees.
6. A piston ring assembly according to claim 1, wherein said upper ring includes a first ring gap and said lower ring includes a second ring gap.
7. A piston ring assembly according to claim 1, wherein said upper and lower rings each include a lip extending about an outer periphery thereof.
8. A piston ring assembly according to claim 1, wherein one of said upper ring and said lower ring include a plurality of projections on a mating inner surface to define a plurality of vents.
9. A piston ring assembly for retention in a ring groove of a piston of an internal combustion engine, comprising:
an upper ring for bearing against an upper surface of the piston ring groove, said upper ring defining a first shoulder recess about an inner periphery thereof;
a lower ring for bearing against a lower surface of the piston ring groove, said lower ring defining a second shoulder recess about an inner periphery thereof, wherein a first portion of said upper ring is in direct contact with a corresponding first portion of said lower ring;
said first and second recesses defining a cavity; and
a generally sinusoidal expander received in said cavity, said generally sinusoidal expander having alternating apexes, said apexes adapted to contact second corresponding portions of said upper and lower rings, wherein radial compression of said upper and lower rings induces axial expansion of said generally sinusoidal expander for urging said upper and lower rings against the upper and lower surfaces of the piston ring groove.
10. A piston ring assembly according to claim 9, wherein said generally sinusoidal expander includes two ends defining an expander gap such that radial compression of said upper and lower rings mates said two ends, thereby closing said expander gap and said mated two ends form a generally W-shaped configuration.
11. A piston ring assembly according to claim 9, wherein said apexes of said expander are generally flat and are supported by two adjacent leg members such that an angle defined by said adjacent leg members is about 16 degrees.
12. A piston ring assembly according to claim 9, wherein said upper and lower rings each include a lip extending about an outer periphery thereof.
13. A piston ring assembly according to claim 9, wherein said upper ring includes a first ring gap and said lower ring includes a second ring gap.
14. A piston ring assembly according to claim 9, wherein one of said upper and lower rings include a plurality of projections on a mating inner surface to define a plurality of vents.
15. A piston ring assembly according to claim 1, wherein the apexes comprise a set of upper apexes and a set of lower apexes, the set of upper apexes is spaced apart from the set of lower apexes in the axial direction of the expander, the set of upper apexes contacts the second portion of the upper ring, and the set of lower apexes contacts the second portion of the lower ring.
16. A piston ring assembly according to claim 9, wherein the apexes comprise a set of upper apexes and a set of lower apexes, the set of upper apexes is spaced apart from the set of lower apexes in the axial direction of the expander, the set of upper apexes contacts the second portion of the upper ring, and the set of lower apexes contacts the second portion of the lower ring.
17. A piston ring assembly according to claim 3, wherein said cavity has a radial thickness, said expander has a radial thickness, and said expander radial thickness is greater than said cavity radial thickness.
18. A piston ring assembly according to claim 9, wherein said cavity has a radial width, said expander has a radial width, and said expander radial thickness is greater than said cavity radial width.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
What we claim is:
1. A liquid crystal display element comprising:
a pair of substrates provided opposite to each other having an electrode on at least either of said substrates;
a resin layer formed on at least either of said pair of substrates;
alignment films having surface energy of 51 to 60 dyncm formed on surfaces of said pair of substrates respectively; and
a liquid crystal composition charged in a gap between said pair of substrates with said alignment films provided opposite to each other.
2. A liquid crystal display element according to claim 1, wherein said resin layer is a color filter layer.
3. A liquid crystal display element according to claim 1, further comprising:
a plurality of pixel electrodes; and
a plurality of driving elements connected to said pixel elements, wherein said pixel electrodes are provided on said resin layer, said substrate having said resin layer is an array substrate, and said alignment films are formed on said plurality of pixel electrodes.