motor vehicles"

DESCRIPTION

This invention relates to a motive unit particularly but not exclusively, for motor vehicles.

As is known, motor vehicles are currently propelled by assemblies basically comprised of an internal combustion engine, a gear box transmission, and a friction clutch. This solution, while being in many ways advantageous, has a source of power dissipation in the clutch area, and requires concurrent actuation of the gear shift lever and clutch pedal by the driver.

Motive assemblies including so-called automatic gear shift systems have also been proposed. This solution does relieve the driver of the need to operate a gear shift lever and a clutch pedal, but still includes sources of power dissipation, this time in the automatic gear shift area.

The underlying problem of this invention is to provide a motive unit which has such constructional and functional features as to overcome the above drawbacks of the prior art and which can, in particular, reduce the driver's intervention to a single operation, while achieving significant savings

in power .

This problem is solved by a motive unit being characterized in that it comprises a rotary internal combustion engine having a cylinder carrying rotor and a crankshaft, arranged to counter-rotate relative to each other, a power takeoff connected through to the crankshaft, a differential system wherein a planet gear spider is made rigid with the crankshaft for rotation therewith and carries rotatively two interlinked planet gears, the one in mesh engagement with an action side gear rotatively rigid with the rotor and the other in mesh engagement with a reaction side gear supported rotatably on the framework, and a one-way drive between the rotor and the reaction side gear to allow of reverse rotation of the reaction side gear at a predetermined angular velocity.

Further features and the advantages of the motive unit of this invention will become apparent from the following description of an embodiment thereof, given by way of example and not of limitation with reference to the accompanying drawing figures which show:

Figure 1, an elevation view in longitudinal section, taken along line I-I , of a unit according to the invention;

Figures 2, 3 and 4, cross-sectional views of the unit shown in Figure 1, taken along lines II-II, III-III and IV-IV, respectively;

Figure 5, a part-sectional plan view of the unit shown in Figure 1, taken along line V-V;

Figure 6, a schematic view of the unit shown in Figure 1;

Figure 7, a schematic perspective view of part of the unit shown in Figure 1;

Figure 8, a schematic view of a detail of the unit in Figure 1, drawn to an enlarged scale.

Figure 9, an exploded view showing schematically modified embodiments of the unit according to the invention;

Figure 10, a diagram illustrating the operation of the unit of Figure 1 and 9.

With reference to the drawing views, generally shown at 1 is a motive unit for motor vehicles according to the invention.

The motive unit 1 stands on a framework 2 composed of a cradle-like open structure accommodating a rotary internal combustion engine 3. The framework 2 is integral with an enclosure formed by a casing 40 which contains a differential system 4, a one-way drive 5, a reverse system 6, and a power takeoff 7.

The rotary internal combustion engine 3 comprises, under a sheet metal shroud 8 mounted on the framework 2, a cylinder carrying rotor 9 and a crankshaft 10, with the rotor 9 and the crankshaft 10 being set for counter-rotation.

Specifically, the rotor 9 is mounted rotatably in bearings 11 and 12 on the crankshaft 10, and the rotor-shaft assembly is mounted rotatably in the framework 2 by means of a bearing 13 housed in an end wall of the framework 2 and a bearing 14 housed in an end wall of the casing 40.

The bearing 13 is located at one end 10a of the crankshaft 10 which juts out from the rotor, the other end 10b of the crankshaft 10 jutting out from the opposite end of the rotor. Connected through to said end 10b is the power takeoff 7.

The bearing 14 locates at a tubular extension 9a of the rotor through which the crankshaft is passed.

The cylinder carrying rotor 9 has two opposed cylinders 15 and 16 with two respective pistons 17. and 18 which are connected to a common crank 19 of the crankshaft 10 by respective connecting rods 20 and 21, specifically a plain rod and a double rod.

The engine 3 is preferably a two-stroke cycle engine having an air intake duct 22 that leads to

scavenging ports 23 and 24 formed in the rotor, and an exhaust duct 25 extending from a manifold 26 into which there open exhaust ports 27 and 28 formed in the rotor.

Provided in the intake duct 22 is a supercharging blower 29 which comprises a first impeller 30 attached to the rotor, a second impeller 31 attached to the crankshaft, and a third impeller 32 attached to the rotor.

An fuel/air mixing means is associated with the intake duct.

The differential system 4 comprises a planet gear spider 41 which is made rotatively rigid with the crankshaft 10 and carries a shaft 41 rotatably thereon which has two planet gears 43 and 44 keyed to its ends, whereby the planet gears are interlinked for rotation. The differential system 4 further comprises an action side gear 45 which is keyed to the rotor extension 9a for rotation therewith, and a reaction side gear 46 which is supported on the casing 40 for idle rotation, specifically around the crankshaft 10.

Of the two planet gears 43 and 44, planet gear 43 is enmeshed with the action side gear 45, whereas planet gear 44 meshes with the reaction side gear 46.

The one-way drive 5 extends between the rotor

9 and the reaction side gear 46.

In particular, the drive 5 is accommodated within the casing 40 and comprises a pair of gear wheels 52 and 53 arranged with their axes orthogonal to each other at a drive ratio of 1:1, a mechanical speed variator 57 of the type having a pair of conical pulleys 58 and 59 with a drive belt 60 and a control joystick 61, a one-way drive pair 62 comprising a worm screw 63 and a wheel 64 at a high step-down drive ratio, e.g. of 1:20, and a pair 65 comprising a gear wheel 66 and a pinion gear 67 at a high step-up drive ratio, specifically equal to the step-down drive ratio of the pair 62.

The wheel 52 is rigid with the gear 45 for rotation therewith, and is also keyed to the extension 9a. The pinion gear 67 is rigid with the gear 46 and also an idler around the crankshaft 10.

Shown at 70, 71, 72 and 73 are shafts which ' are carried rotatably in the casing 40 and retained axially by respective thrust bearings. Respectively keyed to such shafts, for joint rotation therewith, are the wheels 53 and 55, the wheel 56 and pulley pair 58, the pulley pair 59 and worm screw 63, as well as the wheel 74 and wheel 76.

In the drive 5, the worm screw 63 of the

one-way pair 62 is connected through to the rotor 9, whereas the wheel 64 is connected through to the reaction side gear 46.

The reverse system 6 is placed between the crankshaft 10, on the end 10b thereof, and the power takeoff 7.

It comprises, within a casing 80 integral with the casing 40, a sleeve 81 which is fitted for idle rotation over the crankshaft end 10a and carries the power takeoff 7. This sleeve is formed with a splined land 82.

A clutch 83 is movable along the splined land 82 and rotatively rigid with it, said clutch being shiftable, by means of the joystick 61, between a first position where it engages a bevel gear 84 keyed to the crankshaft, whereby the power takeoff 7 will be rotated in the same direction as the crankshaft, and a second position where it engages a bevel gear 85 being an • idler around the sleeve in mesh engagement with a bevel gear 86 journalled on the casing and at the same time in mesh engagement with the bevel gear 84 as well, whereby the power takeoff 7 will be rotated counter-directionally to the crankshaft.

In the drive 5, the worm screw 63 functions as a stop to the unrestricted idle rotation of the

wheel 64, and hence of the reaction side geaar 46.

In particular, the worm screw 63, which revolves in the direction of arrow 63a, functions through its worm 63b as a rearward movable stop to the unrestricted idle rotation of the gear wheel 64. The gear wheel 64 is rotated controllably in the direction of arrow 64a by the constant engagement of a tooth 64b thereof with the worm 63b.

The worm 63b reacts to component forces Rl and R2 and resultant force R, while dodging them, which the tooth 64b of the gear wheel 64 is applying continually to it, and hence, to the thrust bearing of the shaft 72 and ultimately to the framework 2.

The drive 5 allows of a rearward rotation of the reaction side gear 46 at a predetermined angular velocity being a function of the drive ratio to which the speed variator has been set by means of the joystick.

In particular, the variator setting can provide, in the manner explained hereinafter, a drive ratio of unity, whereby the reaction side gear will be turning at the same speed as the action side gear, that is as the rotor. In this case, the angular velocities of the crankshaft and the power takeoff would be zero, and the vehicle at rest.

On the other hand, with the variator set for a drive ratio in the zero region, the reaction side gear will be virtually stationary. In this case, the crankshaft would be turning at the same speed as the rotor but in the opposite direction, and the vehicle travelling at full speed.

II matters to observe that most of the drive 5, and specifically that portion of it which includes the pair 51, pair 54, and variator 57, may be made quite light because that drive portion is practically subjected to no strains. In fact, the large forces applied by the rotor to the reaction side gear are transferred to the worm screw, which acts as a stop on account of its irreversible feature.

The only forces which the drive is to withstand are those needed to rotate the worm screw. These forces are quite small because they are to drive the worm screw in the same direction as the worm screw would turn of its own account if it were not for its irreversible feature.

It is also important to notice that the internal combustion engine 3, being a two-stroke cycle type and having counter-rotating crankshaft and cylinder carrying rotor, would have, in the twin cylinder embodiment described above, four power strokes

per revolution, which is apt to result in reduced bulk for a given power output.

In modified embodiments (see Figure 9) of the invention, this motive unit 1 comprises, instead of the rotary internal combustion engine, a rotary prime mover which is either an electric motor 90 having a rotor 91 and a shaft 92, being complete with respective windings and arranged for counter-rotation from each other, or a gas turbine 95 having a rotor 96 and a shaft 97, being complete with respective blandings and also arranged to counter-rotate with respect to each other.

The motive unit of this invention can be used, in its electric motor embodiment to drive machine tools, transfer machine lines, hoisting equipment, and general industrial equipment. In its gas turbine embodiment, it lends itself for rail traction and the like.

The operation of the unit 1 is summarized by the formulae and the graph in Figure 10, where A is the angular velocity of the rotor 9, B the angular velocity of the driveshaft 10, and C the angular velocity of the reaction side gear 46.

By manipulating the joystick control of the variator, the angular velocity C can be varied between a zero and a maximum value nominally assumed to be 20.

When C=0, B=A and the output speed at the power takeoff 7 is at a maximum. When C=20, B is zero and a neutral condition is entered. Under this condition, A becomes 20. In an intermediate condition, such as with C=10, B=5 and the output speed at the power takeoff 7 is one half the maximum speed.

A major advantage of the motive unit according to the invention is that the motor vehicle can make a standing start with the gears in constant mesh without resorting to any friction clutch or automatic gear shift transmission, and hence without the power losses that these involve.

Another advantage is that it can lighten the driver's task, since he/she would only have to operate a single joystick to both change of speed and reverse its direction of travel, where desired.

In addition, this unit is simple construction-wise and of reduced volume, a non-least advantage in mass production methods.

Finally, the motive unit of this invention has in actual practice a wide range of possible applications, by that it makes best use of the features of internal combustion engines, electric motors, and gas turbines.

Of course, a person of skill in the pertinent

art may make several modifications and changes unto the unit described, with a view to filling contingent and specific demands, without departing from the protection scope of the invention as defined in the appended claims.