GB2103755A

GB2103755A - Mechanism having a reciprocating member coupled to a rotary member

Info

Publication number: GB2103755A
Application number: GB08124293A
Authority: GB
Inventors: Henry Eddington Roberts
Original assignee: Individual
Current assignee: Individual
Priority date: 1981-08-08
Filing date: 1981-08-08
Publication date: 1983-02-23

Abstract

This invention is to reduce stresses in the gears of hypocycloid machines when used for converting reciprocating motion to rotary motion, particularly when applied to internal combustion engines. The invention provides for the shaft carrying the pinion 16 which meshes with the annulus 21 to incorporate a flywheel 29 or flywheels. The load applied through the connecting rod big end bearing 23 causes rotation of the pinion shaft and hence applies forces to the gear teeth of the pinion 16. The effect of the flywheel 29 fixed to the pinion shaft is, by its inertia, to reduce the peak loads on the gear teeth beneficially. <IMAGE>

Description

SPECIFICATION Improvements in or relating to machines having a reciprocating member coupled to a rotary member This invention relates to machines having a reciprocating member coupled to a rotary member and more particularly to internal combustion engines having one or more reciprocating pistons driving a rotary power output shaft.

In my Patent Specifications Serial Nos.

1094649 and 1460890 1 have described constructions of internal combustion engines in which a piston reciprocating within a cylinder is coupled to a rotary output shaft or shafts by means of a toothed pinion or pinions mounted for rotation about an axis parallel to and eccentric relative to the output shaft. The teeth of each pinion engage with a stationary ring of internal teeth within the crankcase. A connecting rod, secured to the piston, is connected to the pinion by a big end bearing carried eccentrically on the pinion, the diameter of the pitch circle of the pinion is equal to half the diameter of the pitch circle of the ring of stationary teeth and the eccentricity of the big end bearing on the pinion is such that the axis of the big end bearing lies on the pitch circle of the pinion.As a result the motion of the axis of the big end bearing is along a straight line and hence the connecting rod also moves with a reciprocating motion along a straight line. Therefore the connecting rod may be connected rigidly to the piston.

According to the present invention a machine includes a pinion shaft, a toothed pinion rigidly attached to a flywheel mounted on said shaft, a rotational bearing between said pinion and a reciprocable member, the axis of the bearing extending parallel to the axis of rotation of the pinion and through the pitch circle of the pinion; output shaft means rotatable about an axis parallel to the axis of rotation of the pinion and providing supports for the pinion shaft on opposite sides of the rotational bearing, said supports being eccentric relative to the axis of the output shaft means; and a ring of stationary teeth engaging the pinion, the pitch circle diameter of the teeth being twice the pitch circle diameter of the teeth being twice the pitch circle diameter of the pinion, to control rotation of the pinion to cause the axis of the bearing to reciprocate along a straight line.

The new feature of my present invention is the provision of a flywheel or flywheels fixed to the pinion or pinions, the flywheel inertia having the effect of reducing the forces on the teeth of the pinion(s). As the pinion(s) rotate at twice crankshaft speed, flywheels attached to the pinions will be more effective than normal flywheels of similar size.

An embodiment of my invention will now be described, by way of example, with reference to the accompanying drawings in which: Figure 1 shows an axial cross section of part of an internal combustion engine, and Figure 2 shows a sectional view on the line A-A of Figure 1.

Referring to the drawings, a crank pin 10 is supported at one end in a suitable bearing in a first crankshaft member 11 and at the other end in a suitable bearing in a second crankshaft member 12, these bearings being indicated diagramatically at references 1 7 and 18. Both crankshaft members 11 and 12 have a common axis 13 about which they are rotatable in a crankcase 14.

The crank pin 10 is supported in the crankshaft members 11 and 1 2 eccentrically relative to the axis 1 3 so that they rotate in unison about their axis 13. Pinions 1 5 and 1 6 are secured to the crank pin 10 so that they are coaxial with bearings 17 and 18.The axis of the part of the crank pin which forms the big end bearing hub 19 is eccentric relative to the axis of rotation of -the crank pin such that the axis of the big end bearing hub extends through the pitch circle of the teeth of the pinions 1 5 and 1 6. Internally toothed rings 20 and 21 are secured to the crankcase 14 to mesh with the teeth of pinions 1 5 and 1 6. The diameter of the pitch circle of the rings of teeth 20 and 21 are twice the diameter of the pitch circle of the teeth of the pinions 1 5 and 1 6 and the axes of the crankshaft members, the crank pin and the big end bearing are parallel to one another. A connecting rod 22 has a big end 23 engaging around the big end bearing hub 19 and the opposite end of the connecting rod 22 is rigidly secured to a piston 24 which is reciprocable in a cylinder 25.The end of the cylinder 25 remote from the crankcase 14 is closed by a conventional cylinder head (not shown) and suitable valves for the intake of fuel mixture and exhaustion of combustion products are also provided. As explained in greater detaii in my Patent Specification Serial No. 1094649, the engagement of the pinions 1 5 and 1 6 with the toothed rings 20 and 21 and the relative pitch circle diameters of the pinions 1 5 and 1 6 being as described above, upon rotation of the crankshaft members 11 and 12, the axis of the bearing hub 1 9 is caused to have a reciprocating motion along a straight line passing perpendicularly through the axis of the crankshaft members 11 and 12.

The cylinder 25 is positioned so that the straight line passes centrally along the length of the length of the cylinder and hence it will be realised that this straight line reciprocating motion of the big end bearing permits the piston to be rigidly secured to the connecting rod 22.

The crankshaft members 11 and 12 carry balance weights 26 and 27 respectively and these together with the supplementary balance weights incorporated in the flywheels 28 and 29 on the crankpin 10 enable the unbalanced forces - produced by the rotation of the crankshaft members and the crank pin and by the reciprocation of the connecting rod and piston to be counterbalanced to reduce vibration of the engine to negligibie amount.

An opposed twin cylinder engine may be constructed by securing a second connecting rod to the connecting rod 22 so as to extend diametrically opposite to the rod 22 and rigidly securing a second piston on the end of the second rod which reciprocates within a second cylinder.

Also additional big end bearing hubs may be provided on the crank pin, the hubs and pinions 15, 16, being rigidly interconnected, for example by constructing them integrally, to permit additional pistons in cylinders displaced along the axis 13 to be connected to the pinions and hence to the crankshaft members. Such additional cylinders may be arranged side by side, in line or may be disposed at an angle to one another, the big end bearing hubs being suitably arranged eccentrically on the pinions 1 5, 1 6 according to the arrangement of the cylinders.

While the above described embodiments have related to internal combustion engines, it is to be understood that my invention may be utilised in other machines in which it is desired to drivingly connect a reciprocable member with a rotatable member, for example, a pump having a piston reciprocating in a cylinder may have the driving shaft connected to the piston as described above.

Claims

1. A machine including a pinion shaft; a toothed pinion mounted on said shaft, a rotational bearing between said pinion and a reciprocable member, the axis of the bearing extending parallel to the axis of rotation of the pinion and through the pitch circle of the pinion; output shaft means rotatable about an axis parallel to the axis of rotation of the pinion and providing supports for the pinion shaft on one side or both sides of the rotational bearing, said supports being eccentric relative to the axis of the output shaft means; and a ring of stationary teeth engaging the pinion, the pitch circle diameter of the teeth being twice the pitch circle diameter of the pinion, to control rotation of the pinion to cause the axis of the bearing to reciprocate along a straight line, and a flywheel rigidly secured to a pinion.

2. A machine as claimed in claim 1 in which the output shaft means consists of first and second crankshafts having a common axis of rotation and in which the pinion shaft extends between and is rigidly secured adjacent each end of the pinion shaft to the first and second crankshafts respectively, the pinion and flywheel and rotational bearing being freely rotatable about said pinion shaft.

3. A machine as claimed in claim 1 in which the output shaft means consists of first and second crankshaft having a common axis of rotation and means to constrain the first and second crankshafts to rotate about said common axis in unison and in which the pinion shaft with flywheel is supported in a rotatable manner at each end thereof in the first and second crankshafts respectively.

4. A machine as claimed in claim 1 in which the output shaft means consists of a first crankshaft member only at one side of the machine in which the pinion shaft and flywheel is supported in a rotatable manner.

5. A machine as claimed in any preceding claim including a further rotational bearing between the pinion and a further reciprocable member.

6. A machine as claimed in any preceding claim including a further flywheel or flywheels rigidly connected to the pinion or pinions.

7. A machine as claimed in any preceding claim in which a flywheel incorporates a balance weight.

8. A machine as claimed in any preceding claim including a piston rigidly secured to the reciprocable member and a cylinder in which the piston is movable in a reciprocating motion.

9. An internal combustion engine including machine as claimed in any preceding claim.

10. A machine constructed and arranged to operate substantially as hereinbefore described with reference to the accompanying drawings.

11. An internal combustion engine constructed and arranged to operate substantailly as hereinbefore described with reference to the accompanying drawings.