AU2011201501B1 - Improvements to radial rotary fluid pressure machines - Google Patents

Abstract

A radial rotary fluid pressure machine including: a stator including an interior face formed as a surface of revolution of substantially constant radius about a 5 longitudinal axis; a rotor including: a contact face formed as a surface of revolution about the longitudinal axis for relative sliding rotation with respect to the interior face of the stator as well as relative axial movement along the longitudinal axis; one or more cylinders extending 0 substantially radially with respect to and having a radial axis substantially radial to the longitudinal axis; a piston sealingly slidable in the or each cylinder along the or each radial axis; a connecting rod connecting the or each piston to a crank shaft; one or more sets of ports penetrating the 5 interior face of the stator at predetermined circumferential and axial locations with respect to the longitudinal axis, the number of sets corresponding to one or a multiple of the number of pistons and cylinders; linking means linking the rotor and the crank shaft for rotation relative to the stator !0 at predetermined speeds and directions of rotation; and adjustable connection means for connecting the drive means to the crank shaft and the rotor independently of the position of the rotor in the stator along the longitudinal axis.

Description

1 IMPROVEMENTS TO RADIAL ROTARY FLUID PRESSURE MACHINES This invention relates to improvements to radial rotary fluid pressure machines. The invention has particular application to improvements to radial rotary fluid pressure 5 machines disclosed in International Patent Application No. PCT/NZ1998/000159. However, the invention may also have application to sealing other types of radial rotary fluid pressure machine. The radial rotary fluid pressure machine disclosed in the [0 aforementioned International Patent Application provided a stator, a first surface formed on an interior face of the stator as a surface of revolution about a first axis, a rotor, a second surface formed on part of the rotor as a surface of revolution about the first axis. The first and second surfaces L5 are mounted for relative sliding rotation with respect to one another. A plurality of cylinders is formed in the rotor and extend substantially radially with respect to the first axis. Each piston is sealingly slidable axially in each cylinder and has a connecting rod connecting the pistons to a crank shaft 20 in similar fashion to standard internal combustion engines. A plurality of ports is formed in the stator extending through the first surface at predetermined circumferential locations in the stator corresponding in number to the number of pistons and cylinders. The ports are provided for passing fluid 25 passing to or from each cylinder through each port 2 corresponding to each cylinder. Drive means interconnects the rotor and the crank shaft, the drive means being arranged to rotate the rotor and the crank shaft relative to the stator at predetermined speeds and directions of rotation. The pistons 5 and cylinders are arranged such that, in use, an area of said first surface swept by each cylinder is different from an area of said first surface swept by the or any other cylinder or cylinders. For convenience, this type of radial rotary fluid pressure machine will be referred to herein as my previous [0 radial rotary fluid pressure machine Whilst my previous radial rotary fluid pressure machine performed satisfactorily, the interconnection of the rotor and crank shaft was provided in such a way that the stator was provided as a fixed element when mounting my previous radial [5 rotary fluid pressure machine for use. Additionally, the stator was designed for rotation of the pistons and cylinders therein in fixed disposition. The arrangement limits my previous radial rotary fluid pressure machine in its operation and may also prevent recovery of some of the reactive energy 20 produced in the rotor. The present invention aims to provide improvements radial rotary fluid pressure machines which alleviate one or more of the aforementioned problems, or at least to provide an alternative arrangement of the mechanical connections between 25 the stator, rotor and crankshaft. Other aims and advantages of 3 the invention may become apparent from the following description. With the foregoing in view, in one aspect the present invention resides broadly in a radial rotary fluid pressure 5 machine including: a stator including an interior face formed as a surface of revolution of substantially constant radius about a longitudinal axis; a rotor disposed within said stator and including: LO a contact face formed as a surface of revolution about the longitudinal axis for relative sliding rotation with respect to the interior face of the stator as well as relative axial movement along the longitudinal axis; L5 one or more cylinders extending substantially radially with respect to, and having a radial axis substantially radial to, the longitudinal axis; a piston sealingly slidable in the or each cylinder along 20 the or each radial axis; a connecting rod connecting the or each piston to a crank shaft; one or more sets of ports penetrating the interior face of the stator at predetermined circumferential and axial 25 locations with respect to the longitudinal axis, the number of 4 sets corresponding to one or a multiple of the number of pistons and cylinders; linking means linking the rotor and the crank shaft for rotation relative to the stator at predetermined speeds and 5 directions of rotation; and adjustable connection means for connecting the drive means to the crank shaft and the rotor independently of the position of the rotor in the stator along the longitudinal axis. .0 The radial rotary fluid pressure machine may be a pump or a motor. In the form of a motor, it is preferred that the sets of ports each include an inlet port, an exhaust port and a sparking port for the motor being in the form of an internal combustion engine. A different arrangement of ports may be .5 provided for a compression ignition engine. Preferably, the sets of ports are arranged for different operating conditions of the motor at two or more axial locations. For example, one set of ports may provided for operating the motor with a light load and another may provided for operating the motor with a 20 heavy load. It is also preferred that the connecting rod for each piston be independently connected to the crank shaft, as opposed to having the connecting rod of one piston directly connected to the crank shaft and the remainder of the 5 connecting rods of the other pistons connected to the crank shaft end of the connecting rod of the first piston. In the form of a pump, it is preferred that a set of ports be provided to shunt pumped fluid from the outlet to the 5 inlet to permit the pump to be started under substantially no load. A set of ports may be provided for normal pumping operations. Additionally, different sets of ports may be provided for pumping at high pressure and low flow and for low pressure and high flow. LO In another form, the fluid pressure machine may incorporate one set of ports to operate as a pump and another set of ports to operate as an engine. In order that the invention may be more readily understood and put into practical effect, an exemplary L5 embodiment of the present invention will now be described with reference to the following drawings, and wherein: Fig. 1 is a diagrammatic cross section transverse to its longitudinal axis of a radial rotary fluid pressure machine according to the invention; 20 Fig. 2 is a diagrammatic sectional view of part of a stator of the radial rotary fluid pressure machine of Fig. 1; 6 Fig. 3 is a diagrammatic cross section along the longitudinal axis of the radial rotary fluid pressure machine of Fig. 1; and Fig. 4 is a diagrammatic representation illustrating the 5 working of a drive coupling for a radial rotary fluid pressure machine according to the invention. The radial rotary fluid pressure machines 10 illustrated in Figs. 1 to 4 includes a rotor 11 mounted for rotation about a longitudinal axis 20 in a stator 12. The longitudinal axis .0 is marked with an "X" in Fig. 1. The stator has a substantially cylindrical inner face 13 of circular section. The rotor includes a cylinder 14 having a contact face 15 which is in substantial conformity with the cylindrical inner face of the stator. A piston 16 is mounted for reciprocating .5 motion in the cylinder, the reciprocating motion being radial with respect to the longitudinal axis. However, the radial reciprocating motion also rotates relative to the stator about the longitudinal axis. A connection rod 17 connects the piston to a crank shaft 18, the connection rod having a little end 20 pivot 19 for connecting the piston to the connecting rod and a big end pivot 21 for connecting the connecting rod to the crank shaft. The crank shaft is arranged to convert the reciprocating motion of the piston into rotary motion in the direction of 7 arrow 22 relative to the rotor. The rotary motion of the crank shaft also produces a reactionary rotary motion of the rotor in the direction of arrow 23 with respect to the stator. In the view illustrated in Fig. 1, it will be seen that the crank 5 moves clockwise and the rotor moves anticlockwise. When the crank and rotor are each at 900, they have an angular separation of 1800, thereby permitting, in a relative sense, the Otto cycle to be complete in half the normal revolutions of a normal internal combustion engine. .0 The rotor is fixed to a hollow shaft 24 for transmission of its rotary motion to a take-off assembly 30. The crank shaft extends through the bore of the hollow shaft and contra rotates therewith for transmission of its rotary motion to the take-off assembly. .5 The take-off assembly includes four bevel gears, a proximal sun gear 27 mounted for rotation about the longitudinal axis with the hollow shaft, a remote sun gear 28 mounted for rotation about the longitudinal axis 28 with the crank shaft in the opposite direction to that of the proximal 20 sun gear. The contra rotation of the sun gears is constrained by two planet gears, a first planet gear 29 and a second planet gear 31 which rotates in the opposite direction to the first planet gear. Power may be take off the shafts of the planet gears separately, or they may be linked by a reversing 25 gear to transfer all torque to or from the radial rotary fluid 8 pressure machine. The motor illustrated in Fig. 1 may be considered to be two motors in one, both motors having the same output. The diagrammatic representation 40 shown in Fig. 4 5 includes a representation of the stator 12', rotor 11' and crank shaft 18' using the same reference numerals as in Figs. 1 and 3, but distinguished therefrom by a following apostrophe. A retention member 42 retains a gearbox 43 to the rotor to synchronise the contra rotary motions of the rotor 0 and crank shaft. An output shaft 44 extends from the gearbox to transmit the output of the radial rotary fluid pressure machine when operated as an engine. A relative axial movement is provide between the rotor and stator by a mechanism akin to a lathe bed tool slider .5 mechanism as indicated at 45. The stator is mounted to the mechanism by a stator mounting 46 and the rotor is mounted to the mechanism by a rotor mounting 47, each of which are of a form akin to a lath platform for axial movement of the stator and rotor, each element being the same distance from their 20 respective centres to the (lathe bed) mechanism. Each component is moveable individually or together. The rotor mounting may be moved towards and away from the rotor mounting in a similar fashion to moving a tool along a lathe bed. In so doing, the rotor may be moved axially with respect to the 25 stator to position the rotor at a desired axial disposition in 9 the stator for operation of the radial rotary fluid pressure machine under different conditions as described herein. The rotor consists of a cylinder assembly with corresponding crank shaft, each cylinder being offset by the 5 same amount of degrees as the crank shaft which allow each piston to connect directly to the crank pin, allowing the cylinder and floating seal to rotate in a different path to any other cylinder. Both action and reaction forces are utilised through special gearing and a reaction member to .0 rotate in one direction, the forces being equal to twice the force or the same torque at half the speed. As a result, the relative axial movement of the rotor and stator meets lesser resistance to such movement than would otherwise be the case. Because the stator has a substantially cylindrical inner .5 face, it presents a straight-line axial relative movement capability with respect to the rotor as well as a relative rotary motion capability at any axial position of the rotor in the stator. Such an arrangement permits the rotor to be positioned in juxtaposition to different set of ports for 20 operation under different parameters suited to operation under different conditions. The arrangement of the parts of the fluid pressure machine provides that, when used as an internal combustion engine, there is substantially no torque reaction, or "anti- 10 torque", produced in operation because the radial expansion of combustion gases have no angular restraint, thereby permitting counter rotation of the rotor with respect to the piston and its cylinder. The result provides the same power at half the 5 same speed, or in the same way, twice the power at the same speed, as prior art engines because there is no angular reaction in the engine. If the mechanical ratio constraining movement of the parts is one-to-one, then the crank shaft and the rotor .0 advance by the same angular displacement, but in opposite directions. For example, if the crank shaft is rotated by 1800 one way, then the rotor is rotated by 1800 the opposite way to result in a 3600 relative angular displacement. For a 360' rotation of each component, there is a relative angular .5 displacement of 7200 which corresponds to the four necessary strokes of the Otto cycle for reciprocating internal combustion engines. In other words, the Otto cycle can be fitted into one revolution of the crank shaft from which rotational energy may be drawn from the engine. 20 Although the invention has been described with reference to a specific example, it will be appreciated by persons skilled in the art that the invention may be embodied in other forms within the broad scope and ambit of the invention as herein set forth and defined by the following claims. 25

Claims (8)

1. A radial rotary fluid pressure machine including: a stator including an interior face formed as a surface 5 of revolution of substantially constant radius about a longitudinal axis; a rotor disposed within said stator and including: a contact face formed as a surface of revolution about the longitudinal axis for relative .0 sliding rotation with respect to the interior face of the stator as well as relative axial movement along the longitudinal axis; one or more cylinders extending substantially radially with respect to and having a radial .5 axis substantially radial to the longitudinal axis; a piston sealingly slidable in the or each cylinder along the or each radial axis; a connecting rod connecting the or each piston to a crank 20 shaft; one or more sets of ports penetrating the interior face of the stator at predetermined circumferential and axial locations with respect to the longitudinal axis, the number of sets corresponding to one or a multiple of the number of 25 pistons and cylinders; 12 linking means linking the roLor and the crank shalt ftr rotation at predeterm.-rned speeds and directions of roLation of buLb rrulative to the SLator as wel1 as relative to cach other; and adjustable connecLion means for connecting drive means to the crank shaft and the rotor independently of the position of the rotor in the stator along the longitudina] axis.

2. The radial roLary fluid pressure machine according to 9 Claim 1, and in the form of a motor, wherein the sets of ports each include an inlet port, an exhaust port and a sparking port for the moLor being in the iorm of an internal combustion engine .

3. The radial rotary fluid pressure machine according to Claim 2, wherein the sets of porLs are arranged for different operating conditions of the motor at two or more axial loca Lions .

4. The racial rotary fluid pressure machine according to Claim 1 and in the form of a pump, wherein a set of ports is provided to shunt pumped fluid from Lhe outlet to the inlet to permit the pump to be started under substantially no load. 13

5. The radial rotary fluid pressure machine according to Claim 4, and including a further set of ports for normal pumping operations. 5

6. The radial rotary fluid pressure machine according to Claim 1, and including one set of ports to operate as a pump and another set of ports to operate as an engine.

7. The radial rotary fluid pressure machine according to LO Claim 1, wherein the linking means includes a pair of opposed sun gears and a pair of opposed planet gears arranged for selective engagement of one or both of the planet gears with one or both of the sun gears. L5

8. The radial rotary fluid pressure machine according to Claim 7, wherein both planet gears are engaged with both sun gears, and each planet gear is mechanically linked to the other through a reversing gear. 20 Dated this 4 t day of April, 2011. Anthony Leonardus Wondergem By his Patent Attorneys AHEARN FOX