EP0954682A1

EP0954682A1 - Power machine valve control

Info

Publication number: EP0954682A1
Application number: EP97932118A
Authority: EP
Inventors: Gunnar Leijonberg
Original assignee: Gul & Co Development AB; Gul and Co Dev AB
Current assignee: Gul & Co Development AB; Gul and Co Dev AB
Priority date: 1996-07-12
Filing date: 1997-07-10
Publication date: 1999-11-10
Also published as: SE507208C2; WO1998002644A1; SE9602757L; JP2000515215A; SE9602757D0; AU3565297A

Abstract

The present invention is for the kind of power machines, engines or compressors which have two or more pistons which work against each other, preferably with a common combustion or compression chamber in a stationary cylinder and where the power is transmitted to a rotating movement without an intermediate crankshaft. It is an object of the present invention to obtain such power machine having a simple valve control means. One such device has two parallel plane discs, one stationary disc (8) and one relatively thereto rotating disc (13). The stationary disc (8) is mounted to a housing (9) and the disc (8) in turn has one in its centre positioned cylinder (1) with two end walls (2, 3). In the cylinder there are two pistons (4, 5) which are working pistons of a combustion engine and have a common combustion chamber. At the centre of the cylinder bore adjacent to the upper dead centres, UDC, of the pistons and at opposite sides thereof there are two valves (50, 51). The valve shafts at the ends which are turned only from the cylinder contact a controlling curve or surface (56) which is a part of the rotating disc. On the control curve there are raised parts (57, 58) at which the valves are opened when disc rotates.

Description

Power Machine Valve Control

The present invention is for the kind of power machines, engines or compressors which have two or more pistons which work against each other, preferably with a common combustion or compression chamber m a stationary cylinder and where the power is transmitted to a rotating movement without an intermediate crankshaft .

At known such engines the valve control means are very complicated. It is an object of the present invention to obtain such power machine having a simple valve control means.

By combustion engines the transmission of force from a to and fro motion to a rotating motion is generally by means of some kind of crankshaft or the like means. In certain cases crankshafts are however less suitable and this is especially the case when to and fro movements of different, often opposite directions jointly shall be transferred into a rotating motion. This concerns especially the kind of power machines, 1. e. combustion engines, compressors or pumps where two pistons at the same time work against each other in a common cylinder bore. In these cases the use of crankshafts brings with it complicated mechanical designs to put together the force from the two pistons into a common rotating motion. The transmission of force between a to and fro motion and a rotating motion can instead be by means of a ball bearing which runs in different tracks and comprises a ball which is surrounded by a ballholder which is attached to a piston rod for each ball or to a corresponding device for transmission of the linear movement.

One such device has two parallel plane discs, one stationary disc and one relatively thereto rotating disc. In a cylinder which is positioned central relative to the discs, there are two pistons which are working pistons of a combustion engine having a common combustion chamber. Firmly joined to each of the pistons is a piston rod which at its opposite end has a holder means for the ball by which the force from the to and fro motion is transferred to the rotating disc. The balls also serve as bearing between the stationary disc and the rotating disc. The rotating disc is mounted to a holder which in turn is mounted to an outgoing shaft from which the rotating force is taken for various driving purposes. The balls move both in linear tracks in the fixed disc and in a common elliptic or otherwise closed track in the rotating disc. It is also possible to exchange the balls for other means having a corresponding function for example rolls or pins which roll or slide in the tracks. In other embodiments the tracks may be substituted for by protruding edges contacting for example roller or slide bearings of the sides of the edges.

The invention will below be described more in detail with reference to the embodiment which is shown in the enclosed figures .

Figure 1 is a cross-section at right angle to the lengthwise direction of the cylinder of a combustion engine according to the invention.

Figure 2 shows the engine of figure 1 in cross-section in a plane which is essentially parallel to the plane of rotation.

Figures 3-6 show two alternative embodiments having valve springs .

The device shown in the figures has two parallel plane discs, one which is named stationary disc 8 and one relatively thereto rotating disc 13. The stationary disc 8 is mounted to a housing 9 and the disc 8 in turn has one in its centre positioned cylinder 1 with two end walls 2, 3. In the cylinder there are two pistons 4,5 which are working pistons of a combustion engine and have a common combustion chamber.

Firmly joined to each of the pistons 4, 5 is a piston rod 6, 7 which in its opposite end has a holder means 17, 18 for the ball 15, 16 through which the force from the to and fro motion is transferred to the rotating disc 13. The balls 15, 16 also serve as bearing between the stationary disc 8 and the rotating disc 13. The rotating disc 13 is mounted to a holder 10 which in turn is mounted to an outgoing shaft 23 from which the rotating force is taken to be used for various driving purposes. I a preferred embodiment of the invention the centre axis of the cylinder bore coincides with the line of movement of the balls.

The balls 15, 16 are moving both in linear tracks 11, 24 in the fixed disc and in a common elliptic track 12 in the rotating

At the centre of the cylinder bore adjacent to the upper dead centres, UDC, of the pistons and at opposite sides thereof there are two valves 50, 51. In the embodiment shown in the figures these valves are outlet valves. The valves each have a head 52, 53 and a shaft 54, 55. In the cylinder there are corresponding valve seats and the shafts are designed with consideration of the through passages and stearings which are arranged in the stationary parts adjacent to the cylinder. According to the invention the valve shafts at the ends which are turned only from the cylinder contact a controlling curve or surface 56 which is a part of the rotating disc. On the control curve there are raised parts 57, 58 at which the valves are opened when disc rotates. The returning of the valves can be made m known ways by means of valve springs which are not shown in the figures .

In other embodiments which are shown in figures 3-6 the valve springs are made as blade springs 60, 61, 62, 63. The valve springs may then as in the embodiment of figures 3 and 4 extend themselves outwards-inwards at both sides of the valve shaft, and be kept in position by a faster thereon. The outer ends of the valves then contact their supporting surfaces without any other fastening means . Figures 5 and 6 show an embodiment by which the valve spring is mounted onto the cylinder housing and engages with the valveshaft by a track 64 in the spring allowing a displacement of the surface of contact between the spring and the valve shaft.

In a further embodiment of the invention the valve movements are controlled m both directions by camcurves whereby the valve springs can be eliminated.

In other embodiments of the invention the valve heads and valve seats may be displaced towards the centre of the cylinder thereby that the valve seats are built up from the inner wall of the cylinder. The device will then be designed so that there is enough space between the upper surfaces of the pistons when the pistons are in their UDC. This makes it possible to displace the valve mechanism m its entirety towards the centre and thus reduce the diameter of the camcurve 56.

In other embodiments both the inlet and outlet valves may be arranged in the way which has been described above. The valve shafts of the two kinds of valves then contact camcurves which are adjacent to each other and having somewhat different shape. For this reason the valves are somewhat differently inclined relative to the horizontal plane of figure 1 and the difference m inclination between the two kinds of valves is preferably 5- 10°. When the movement of the pistons, as described above, controls or is controlled by an elliptic track 12 in the rotating disc there are two piston strokes for each round that the disc rotates. In the corresponding way each valve is controlled by an essentially circular surface at the rotating disc, at which surface there are extensions which open the valve once for each round that the disc rotates. Inlet and outlet valves are effected by different circular surfaces whereby the respective extensions are displaced so that the valves open at the desired moments. The arrangement of conventional engine designs which require a camshaft which by a reduction is driven by a crankshaft can m this way be entirely eliminated.

Also embodiments having only one valve in the cylinder bore are possible within the frame of the inventive idea. Preferably this valve is an outlet valve and inlet is through ports, possibly m combination with a forgoing comprimation .

The valve heads 52, 53 are shown in the figures having a circular shape in the surface of the cylinder bore or a corresponding plane. In other embodiments the valveheads may be of elliptic shape in order to better make use of the surface of the cylinder bore which is available when the pistons at the same time are in their upper dead centre, UDC. The valveheads also have a preferably bent surface which follows the shape of the cylinder bore. The shape of the valveheads can also be so designed that they cooperate in controlling the gas flow inside the cylinder and possibly also its inlet and outlet channels.

Claims

1. Device by a power machine having two pistons which are positioned in a common cylinder bore and synchronously work against each other, and means for transmission of power from linear movement of the pistons into rotating movement, which means include a rotating disc (13) and a relatively to the power source stationary second disc, characterized therein that valves (50, 51) are arranged between the upper dead centres, UDC, of the pistons whereby the movements of the valves are controlled thereby that each valve by means of its valveshaft directly contacts a cam curve (56) of the rotating disc (13) .

2. Device according to claim 1 charachterized therein that the cam curve (56) is the circumference of a hole which has been opened n the centre of the rotating disc.

3. Device according to claim 1 or 2 characterized therein that the pistons (4, 5) have a common combustion chamber.

4. Device according to any of the preceedmg claims charachterized therein that the extension of the axis of rotation of the rotating disc passes through the centre point of the cylinder bore between the two pistons (4, 5).

5. Device according to any of the proceeding claims characterized therm that the valves (50, 51) are outlet valves.