Claims
- 1. A mechanism for conversion between reciprocating motion of a reciprocating member and rotating motion of a rotating shaft, comprising:
- a rotatable shaft having a straight portion disposed on an axis of rotation, and an offset portion whose axis extends at an angle to said axis of rotation;
- a hub mounted on said shaft for rotation relative thereto and having one axial end portion axially slidably mounted on said offset portion, and the other axial end portion axially slidably mounted on said straight portion;
- at least one arm mounted on said hub and extending radially therefrom, whereby said arm rocks in a reciprocating arcuate motion when said shaft rotates and said hub nutates relative to said rotating shaft; and
- means for controllably moving said hub axially relative to said shaft, thereby changing the angle of inclination of said hub relative to said shaft axis of rotation to control the stroke of said arm.
- 2. The mechanism defined in claim 1, wherein said hub includes:
- an inner cylinder;
- means slidably and non-rotatably mounting said inner cylinder on said shaft;
- an outer cylinder rotatably mounted on said inner cylinder and non-rotatably connected to said reciprocating member.
- 3. The mechanism defined in claim 2, wherein said mounting means includes a pair of spherical bearings slidably mounted on said shaft for translation thereby, and tiltably mounting said inner cylinder on said shaft, whereby said inner cylinder swirls on said spherical bearings as said spherical bearings translate with respect to said shaft and thereby change the angle of inclination of said hub relative to said shaft axis of rotation.
- 4. The mechanism defined in claim 1, further comprising:
- a cylindrical socket having an axis perpendicular to and intersecting said shaft rotation axis;
- a pin having an axis perpendicular to said socket axis and said shaft rotation axis;
- a cylindrical bore formed in said reciprocating member and rotatably receiving said socket;
- whereby the small lateral and angular components of said arm reciprocating motion as said hub nutates on said shaft are accommodated by rotation of said socket about its axis in said bore, and by lateral movement of said socket in the direction of its axis in said bore.
- 5. The mechanism defined in claim 1, wherein said hub moving means includes:
- a hydraulic cylinder;
- a hydraulic piston mounted in said cylinder for movement relative thereto;
- one of said cylinder and piston being connected to said shaft, and the other being connected to said hub; and
- means for controlling the introduction of hydraulic fluid under pressure from a space of pressurized hydraulic fluid, through a hydraulic fluid passage, and into said cylinder to cause relative translation between said cylinder and said piston and sliding translation of said hub relative to said shaft.
- 6. The mechanism defined in claim 5, wherein said hydraulic fluid introduction control includes:
- an oil port in said other of said cylinder and piston, said oil port communicating between said hydraulic fluid passage and an oil sump;
- a control spool slidably mounted on said other of said cylinder and piston;
- means for moving said control spool;
- whereby said control spool can be moved to a position blocking said oil port whereupon said hydraulic cylinder becomes pressurized with said hydraulic fluid and said hydraulic piston and cylinder more relatively until said oil port begins to clear said control spool and permit leakage of hydraulic fluid from said port at a rate at which the hydraulic fluid pressure force on said other of said cylinder and piston just matches the axial force between said reciprocating member and said arm, whereupon said hub inclination remains fixed.
- 7. The mechanism defined in claim 5, wherein said source of pressurized hydraulic fluid is a pump connected to said shaft.
- 8. The mechanism defined in claim 1, further comprising:
- a balancing wheel mounted on and rotating with said shaft;
- means connecting said balancing wheel and said hub to tilt said balancing sheet when said hub changes its inclination to maintain the dynamic balance of said shaft and its associated rotating structure of all angles of hub inclination.
- 9. The mechanism defined in claim 8, wherein said wheel is mounted on said shaft on a tilting axis perpendicular to said shaft rotation axis and laterally offset therefrom, said tilting axis being offset from the plane of said wheel through the center of gravity thereof, whereby tilting of said balancing wheel changes the distribution of the rotating mass of said wheel with respect to the shaft axis of rotation and with respect to the lateral mid-plane lying through said wheel tilting axis and perpendicular to said shaft axis of rotation, to enable the shaft to be balanced against mass eccentricities with respect to said shaft axis of rotation, and with respect to mass couples which would exert a torque on said shaft about a lateral axis.
- 10. A power control for a Stirling engine having an engine casing enclosing a plurality of working spaces, each containing a reciprocating piston which moves in its working space to cause working gas in said working space to circulate cyclically through a set of heat exchangers including a heater, a regenerator and a cooler to produce a pressure wave in said working space which produces reciprocating motion of a power output member and a mechanism for converting the reciprocating motion of said power output member to rotating motion of an output shaft, said power control comprising:
- means for varying the stroke of said pistons to vary the volume of working gas circulated through said heat exchangers and thereby vary the power absorbed by said working gas from said heater to vary the output power to said power output member, said stroke varying means including an offset portion of said output shaft, a hub linked to said pistons and having a portion mounted on said offset portion for rotation relative thereto and for axial movement therealong, and means for selectively moving said hub along said shaft to vary the angle of inclination of said hub.
- 11. The power control defined in claim 10, wherein said engine is a double acting engine the pistons of which act both to circulate said working gas to produce said pressure wave, and reciprocate under the influence of said pressure wave to control said pressure wave to output power.
- 12. The power control defined in claim 11, wherein said pistons each include a piston rod attached at one end of said piston and attached at the other end of a crosshead, said hub being mounted on said shaft by two journal bearings, both of which can slide axially along said shaft.
- 13. A modified Stirling cycle machine, comprising:
- a casing defining therein a plurality of working spaces each including an expansion space and a compression space;
- means for charging a working gas into said working spaces;
- means for transferring heat to said working gas;
- means for transferring heat from said working gas;
- a regenerator for removing heat from said working gas and then later returning the removed heat back to said working gas;
- means for subjecting said working gas in each said working space to a modified Stirling cycle by heating and expanding said gas in said expansion space, transferring heat between said gas and said regenerator in one direction, cooling and compressing said gas in said compression space, and transferring heat between said gas and said regenerator in the other direction, said subjecting means including a reciprocating member movable in each working space on an expansion stroke wherein said working gas is heated and expands in said expansion space, and movable on a compression stroke wherein said working gas is cooled and compressed in said compression space;
- a rotating power shaft for transmitting power between said machine and an external device;
- a conversion mechanism for converting between the linear reciprocating motion of said reciprocating members and the rotating motion of said power shaft;
- said conversion mechanism including an offset portion of said shaft disposed at an angle to the rotational axis of said shaft, a hub mounted on said offset portion for rotation and axial translation with respect thereto, and means for selectively moving said hub axially on said shaft;
- said hub having a radially disposed arm connecting said hub and said reciprocating member;
- whereby, reciprocating power to and from said reciprocating member is converted by said arm and said hub to and from rotating power of said shaft.
- 14. A Stirling engine comprising:
- an engine casing defining therein a plurality of working spaces adapted to contain a working gas under high pressure, each working space including an expansion space and a compression space;
- a heater for heating said working gas adjacent said expansion space;
- a cooler for cooling said working gas adjacent said compression space;
- a regenerator for removing heat from said working gas as it flows in one direction and for returning the removed heat back to said working gas as it flows in the other direction;
- a linearly reciprocating piston movable in each working space in one direction on an expansion stroke wherein said working gas is heated and expands in said expansion space, and movable in the other direction on a compression stroke wherein said working gas is cooled and compressed in said compression space;
- a power shaft mounted in said casing for rotation about its axis for transmitting rotating kinetic power from said engine to an external load;
- a motion conversion mechanism mounted in said casing for converting the linear reciprocating motion of said reciprocating pistons to rotating motion of said power shaft;
- said conversion mechanism including an eccentric portion of said shaft having an axial gradient of eccentricity to the rotational axis of said shaft, and a hub having a portion mounted on said eccentric portion for rotation relative thereto and for axial movement therealong and so that said hub nutates while said shaft rotates;
- a set of radially extending arms connected to said hub and nutating therewith, said nutating arm motion having an axial stroke component;
- means for selectively moving said hub axially along said shaft operative to change the tilt angle of said hub relative to said shaft axis to change the axial stroke component of said arm motion;
- means for connecting one each of said arms to one each of said pistons, said connecting means forming a power transferring connection between the linear reciprocating motion of said piston and the nutating motion of said arm;
- said connecting means having two portions, which slide radially relative to each other and which rotate relative to each other about two orthogonal axes;
- whereby the radial and rotational movement of said arm as it nutates is accommodated by said connection means to permit a power coupling with a linear reciprocating piston.
- 15. The engine defined in claim 14, wherein said connecting means includes:
- a crosshead attached to said piston and reciprocating axially therewith;
- means in said crosshead defining therein a radially extending cylindrical bore;
- a cylindrical socket radially slidable in said bore and rotatable about the axis of said socket;
- a boss connected to the end of said arm remote from said shaft axis and received in said socket;
- a pin extending transversely through said boss and into opposite sides of said socket to pin said boss to said socket for axial and radial translation therewith, and for rotation relative thereto about the axis of said pin.
- 16. The engine defined in claim 14, wherein said hub tilt angle changing means includes:
- means slidably and rotatably mounting one end of said hub on said eccentric portion of said shaft;
- means for slidably and rotatably mounting the other end of said hub on a straight axial portion of said shaft;
- means for shifting the position of said hub axially along said shaft whereby said one end of said hub moves at an angle to said shaft axis while said other end moves axially, thereby causing said hub to tilt with respect to said shaft axis.
- 17. The engine defined in claim 16, wherein said position shifting means includes:
- a hydraulic piston and a hydraulic cylinder connected, one to said shaft and the other to said hub, and defining a hydraulic chamber between said piston and said cylinder;
- means for pressurizing said chamber with hydraulic fluid to cause relative movement between said piston and said cylinder, and thereby cause movement of said hub relative to said shaft.
- 18. The engine defined in claim 17 further comprising:
- a valve having a valve member movable relative to said shaft for controlling the volume of hydraulic fluid in said hydraulic chamber and thereby control the degree of relative movement of said piston and said cylinder.
- 19. The engine defined in claim 18, wherein said valve comprises:
- a hydraulic fluid port communicating between said hydraulic chamber and an oil sump;
- a spool valve axially movable along said shaft between a fixed position covering said port and preventing escape of hydraulic fluid from said chamber, and a second position uncovering said port and allowing the escape of hydraulic fluid from said chamber.
- 20. The engine defined in claim 19, wherein said other of said piston and said cylinder includes an axially extending tubular section on which said spool valve is mounted and in which said hydraulic fluid port if formed, whereby the axial position of said spool valve can be set and said tubular section will move along said shaft under the influence of increasing or decreasing hydraulic pressure in said hydraulic chamber as said hydraulic fluid enters or escapes from said chamber, until said tubular section moves under said spool valve to the position at which said port is restricted to the extent that the hydraulic pressure in said chamber just balances the axial forces exerted on said hub by said pistons.
Government Interests
The Government of the United States of America has rights to this invention pursuant to Contract No. DEN3-32 awarded by the United States Department of Energy.
US Referenced Citations (9)
Non-Patent Literature Citations (1)
Entry |
Conceptual Design of a Variable Displacement Engine for Automotive Purposes, R. J. Meijer and A. P. J. Michels, Proceedings of the I.E.C.E.C. of Apr. 19, 1978, pp. 1834-1840. |