GB1563498A

GB1563498A - Reciprocating piston engines having piston rotation

Info

Publication number: GB1563498A
Application number: GB4568076A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1976-11-03
Filing date: 1976-11-03
Publication date: 1980-03-26

Description

(54) RECIPROCATING PISTON ENGIN ES HAVING PISTON ROTATION (71) I, RALPH E. SCHREIBER, of 211 East Chicago Avenue, Chicago, Illinois 60611. United States of America, a citizen of the U.S.A., do hereby declare the invention, for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to an engine having a free piston which reciprocates between oppositely located working chambers on an output shaft. An engine is herein defined, as per the Concise Oxford Dictionary, as a mechanical contrivance consisting of several parts. Prior art engines of this type, such as that shown in U.S.Patent Specification No. 1,389.453, have a piston with a square bore which interfits with a square portion of the output shaft to transmit rotary motion of the piston to the output shaft. With this design, difficulty is encountered in sealing the square output shaft in the square bore in the piston and in providing a workable arrangement of rollers on the piston which ride in a groove in the wall of the cylinder. The groove curvature of the prior art is generally limited to sinusoidal configurations.

According to one aspect of the invention there is provided an engine capable of operation as a pump and including a pair of spaced opposed working chambers defined by a cylindrical wall having an inner surface, a piston movable linearly in said working chambers, in response to gas pressure in the chambers and in gas-sealed relation with the cylindrical wall, the piston having end walls with respective cylindrical apertures, an output shaft having cylindrical shaft portions extending through the apertures, guide means on said piston and cylindrical wall to cause guided rotary movement of the piston upon axial movement thereof, and means on the output shaft between the piston end walls for drivingly connecting the output shaft to the piston while allowing sliding relative movement to impart rotary motion to the shaft upon rotation of the piston.

said guide means comprising a track formed in the inner surface of the cylinder wall and inwardly open towards the piston, the track being in a transverse plane with respect to the axis of travel of said piston and limiting travel of the piston between two spaced piston positions, and two guide rollers located in the track and supported for rotation on the piston about a common axis radial with respect to the piston, the rollers having different diameters and the track being defined by a groove bottom wall and first, second and third groove side walls, the first and second side walls being opposite the third side wall with the first side wall joining said bottom wall and being spaced from the third wall a distance less than the distance of the second wall from the third wall, the junction between the first and second side walls providing a shoulder within the track and the smaller diameter roller engaging the first side wall and the larger diameter roller engaging the third side wall.

According to another aspect of the invention there is provided an engine having a piston operatively associated with a pair of spaced opposed working chambers defined by a continuous cylindrical wall, the piston being movable axially and rotatably in the cylinder and means being provided for guiding said axial and rotatable piston movement comprising large and small diameter rollers rotatably supported on said piston for rotation about a common radial axis and a track in extending in an oblique plane around said cylindrical wall having two opposed surfaces and an outwardly offset surface, said rollers being engaged with said opposed surfaces and the offset surface affording clearance with the larger diameter roller and the combined radial distance of said rollers being substantially equal to the maximum spacing between said opposed surfaces.

The invention will now be described by way of example with reference to one embodiment of engine illustrated in the accompanying drawings. In the drawings: Figure 1 is a sectional view of the engine, Figure 2 is an exploded perspective view of the cylinder and piston and output shaft assembly of the engine shown in Figure 1, and Figure 3 is an enlarged fragmentary sectional view of the cam track and roller arrangement provided between the cylinder and piston of the engine shown in Figure 1.

A rotary engine 10 includes a cylinder 12 having opposed cylinder heads 14, 16 and opposed working chambers 18, 20 located on opposite sides of a piston 22. Rectilinear movement of the piston 22 can be caused by combustion of fuel in the working chambers caused by spark plugs, compression ignition in conjunction with fuel injection or other ignition devices (not shown). Alternatively, compressed gases can be employed to cause movement of the piston. The shaft can be powered by an external source (i.e.

an electric motor) and thus operate the engine as a pump.

Means are provided for imparting rotary motion to the piston upon rectilinear movement thereof. In the disclosed construction, said means comprises a cam track 30 in the form of a channel or groove having a groove bottom 32, opposed groove walls 34, 36 and a shoulder having a surface 38 which is inwardly offset from the surface of wall 36.

The cam track 30 is generally oval in con figuration, the oval being formed by the intersection of the cylinder with a plane which is non-normal to the axis of linear movement of the piston 22. The rotarymotion-imparting means also includes two bearings in the form of rollers 40, 42 mounted on a pin 44 for rotation about a common axis which is radial with respect to the axis of longitudinal movement of the piston.

Roller 40 engages the surface 38 and the larger diameter roller 42 engages the surface 34, thus providing continuous engagement of the rollers with the cam track 30 during the complete circuit of the rollers 40 and 42 in the cam track 30. The use of a single roller is not feasible because a certain amount of clearance is required in order to prevent binding of the roller in the groove. However such clearance can cause vibration during use of the engine which will minimise the life of the parts. The use of two rollers as shown eliminates play and thus vibration.

Rotary motion of the piston 22 is transmitted to the output shaft 46 and in the disclosed construction, the output shaft 46 is provided with a block 48 which is fixed thereto and has a length less than that of the piston 22. The block 48, (see Figure 2) which is square in cross-section. fits in a square bore 50 in the piston. Other complementary block cross-sections and bore configurations can be utilised if they provide a rotarv driving engagement between the piston 22 and the output shaft 46. The block 48 is sealed in the bore 50 by piston end walls 52, 54 which have cylindrical apertures 51 with compression and oil sealing rings 58 which seal between bore 50 and the output shaft 46 allowing both sliding and rotary movement. In addition, the end walls 52, 54 can be provided with compression and oil rings 56 to seal the piston to the wall of the cylinder.Piston 22 is of a somewhat smaller diameter than the piston end walls 52, 54 to allow air and oil movement. However, only the rings 56 contact the cylinder 12.

The output shaft 46 can be provided with a tapered surface 60 adjacent each end there of and bearings 62 are disposed in the cylinder heads in engagement with the surfaces 60 to positively locate the shaft 46 with respect to the cylinder 12. A compression plate 67 is fitted to the shaft 46 to seal the bearing area in addition to the use of conventional oil bearing seals. Alternatively compression ring seals may replace plate 67.

Intake and exhaust valve assemblies 64, 66 for each working chamber are shown but are not described in detail because the particular construction thereof is not part of the present invention. Any suitable valving and valve control can be employed for operation in a two or four cycle mode.

Although rotary internal combustion engines having opposed combustion chambers or cylinders are known, engines of this type have not been successful because of sealing difficulties and problems in controlling the guided rotary piston movement. The present invention overcomes difficulties of prior art engines of this type by employing conventional cylindrical piston rings and conventional cylindrical seals to seal the working chambers around the piston and by employing two rollers mounted for rotation about a common axis in engagement with offset walls in the track formed in the cylinder.

Conventional head and cylinder cooling can by employed. Oil circulation is basically conventional with alternative routing and drainage approaches available. Oil can enter the bearings 62 and flow into the hollow shaft 46, over the surface of the block 48, and out through ducts 89 in the piston to the cylinder wall and groove surface, for lubricating the dual rollers 40, 42 and into a small sump (not shown) through the base 32 of the groove. Centrifugal motion and the relative motion between the rider block and piston provide pumping action for movement of the oil throuh the ducts 89.

Several of the engines of this design can be serially connected with the output shafts co-axially arranged. This design also permits the use of various dimensions for the piston diameter, stroke and groove path, which flexibility is not found in other rotary engine designs.

Claims

WHAT I CLAIM IS:-

1. An engine including a pair of spaced opposed working chambers defined by a cylindrical wall having an inner surface.

a piston movable linearly in said working chambers in response to gas pressure in the chambers and in gas-sealed relation with the cylindrical wall, the piston having end walls with respective cylindrical apertures, an output shaft having cylindrical shaft portions extending through the apertures, guide means on said piston and cylindrical wall to cause guided rotary movement of the piston upon axial movement thereof, and means on the output shaft between the piston end walls for drivingly connecting the output shaft to the piston while allowing sliding relative movement to impart rotary motion to the shaft upon rotation of the piston, said guide means comprising a track formed in the inner surface of the cylinder wall and inwardly open towards the piston, the track being in a transverse plane with respect to the axis of travel of said piston and limiting travel of the piston between two spaced piston positions, and two guide rollers located in the track and supported for rotation on the piston about a common axis radial with respect to the piston, the rollers having different diameters and the track being defined by a groove bottom wall and first, second and third groove side walls, the first and second side walls being opposite the third side wall with the first side wall joining said bottom wall and being spaced from the third wall a distance less than the distance of the second wall from the third wall, the junction between the first and second side walls providing a shoulder within the track and the smaller diameter roller engaging the first side wall and the larger diameter roller engaging the third side wall.

2. An engine according to claim 1, wherein seals are provided in the apertures in the piston end walls to prevent transmission of gas from one working chamber to the other and to permit relative movement of the piston with respect to the output shaft.

3. An engine according to claim I, wherein the means on the piston and the cylinder wall to afford rotary movement of the output shaft upon axial movement of said piston comprises an opening in said piston and a body portion on said output shaft fitting in the piston opening, the body portion having a cross section complementary to the piston opening to permit guided axial movement of the piston relative to the output shaft and cause movement of the output shaft upon rG.ry movement of the piston.

4. An engine having a piston operatively associated with a pair of spaced opposed working chambers defined by a continuous cylindrical wall, the piston being movable axially and rotatably in the cylinder and means being provided for guiding said axial and rotatable piston movement comprising large and small diameter rollers rotatably supported on said piston for rotation about a common radial axis and a track extending in an oblique plane around said cylindrical wall having two opposed surfaces and an outwardly offset surface, said rollers being engaged with said opposed surfaces and the offset surface affording clearance with the larger diameter roller and the combined radial distance of said rollers being substantially equal to the maximum spacing between said opposed surfaces.

5. An engine being constructed and arranged to operate substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.