DEVICE FOR DIRECT DRIVING OF WHEELS

Abstract: A device for direct-driving of wheels, adapted for various minivehicles, in particular, for bicycles, motorbikes, or motorcycles. The device comprises a fixed wheel axle (37), a wheel hub (10) rotating about said wheel axle, an engine (15), and transmission units. Said engine and transmission units are enclosed inside the wheel hub; the engine's crankshaft (30) is disposed offset from and parallel to the wheel axle; the transmission units have overrunning clutch means (29). The wheel hub is supported at both sides thereof. The transmission units can be com­ pletely disengaged from the wheel hub when the engine is stopped. A simple, safe and convenient conversion between the manpower-drive mode and the engine-drive mode is ensured on a vehicle equiped with the device.

Description: This invention relates to a device for direct-driving of wheels, in particular to a device for driving the wheels of motorcycles, motorbikes, or motor vans, and it can also be fitted on common bikes. Some means for direct-driving of wheels have already been proposed, for example the device described un US-patent No. 4,132,281 published on January 2, 1979, wherein engine and drive mechanism are arranged in the inner space of a hub between two bike frames as shown in Fig. 1. But in such a device, the crankshaft of the engine was arranged coaxially to the wheel, and the longitudinal symmetrical plane of the engine body was coincide with the symmetrical plane of the wheel. The need of maintaining a certain piston stroke forced the hub to be radially oversized; installing the reduction drive mechanism, magneto and colling fan at the outside of the engine body made the whole device to be axially oversized, as well as overweighted. Furthermore, the support bearing of the hub was offset from the central symmetrical plane of the wheel thereby increasing the load of the bearing and decreasing the stability of the wheel. Besides, it was muscle-consuming to drive the wheel by manpower because that pair of gears had to be driven too when the engine was in rest and was disengaged from the hub. In order to solve the problems mentioned above this inven­ tion proposes a novel device for direct-driving of wheels. Accordingly, it is an object of the present invention to reduce the axial and radial size and the weight of the hub having an engine and transmission units fitted therein, so as to make it suitable for lightweight vehicles, especially for common bikes, while assuring the power output of the engine, the efficiency and reliability of the drive system to be adequate. Further, to support the hub at its both sides, improving the load condition of the hub bearings and the stability of the wheel. Further­ more, to disengage the reduction drive system completely from the hub when the engine is stopped, so as to permit an easy riding by manpower. Still further, to ensure a simple, safe and convenient conversion between the man-­ drive mode and engine-drive mode, as well as an incorpo­ ration of the two. The device for direct-driving of wheels proposed by the present invention can be adapted for various kinds of light-weight vehicles, in particular for motorbikes or motorcycles.The device comprises engine transmission units, a fixed wheel axle, a wheel hub and a set of an actuating mechanism, wherein the engine and the parts of the transmission units are all arranged inside the hub located at the center of the wheel. The said engine mounted in the hub is a two-stroke gasoline engine, the longitudinal axis of the cylinder body therof lies in an orthogonal plane of the wheel axle, or perpendicularly intersects with the axial line of the wheel; the main journals of the crankshaft are offset from an parallel with the wheel axle. The crankshaft has one end thereof mounted with a magneto rotor and another end thereof connected with the transmission units via a clutch; the inner axial distance between said magneto rotor and rotatable members of the clutch is smaller than the diameter of the cylinder bore.The reciprocating piston in the engine cylinder has a recess on its top surface, and a pair of lugs extending from the inner side of the top section forms piston seatings for mounting the piston pin therein. The piston skirt portion has a thin-wall structure, the parts of which near the axial line of the piston pin are cut off to form openings. The vertical distance from the lowest point of the skirt to the axial line of the crankshaft is smaller than the gyro radius of said magneto and clutch means when the piston is at the bottom dead center. In the device according to the present invention an over­ running clutch is used at the last stage of the transmission units to transmit the propulsion power, so that it is possible to rotate the wheel in both forward and backward directions easily when the engine stops. It is also possible to add the manpower to the wheel in case the engine suffers an overload at situation such as when the slope of the road is excessively big. The start system in the device according to the present invention transmits the rotation of the hub to the engine crankshaft through the meshing of a gear clutch in the transmission units. After the engine has been started, the gear clutch turns to get inactive, and the driving force is transmitted by means of the friction of flying-weights of a centrifugal friction clutch and the overrunning clutch, with the result of avoiding the damage of the teeth of the gear clutch. The relative sliding between the flying-weights and the outer dish of the centrifugal friction clutch, and between the driving and driven members of the overrunning clutch can provide protection to the engine and transmission units in case of overload. The impulse-proof type of the gear drive mechnism, for example the spiral tooth gear, arc tooth gear, or involute herringbone tooth gear drive mechnism, may be used in the device to raise the stability and smoothness of power transmission, wherein the rim of at least a big gear is separated from its hub portion, with an elastic ring being fitted in between, in order to reduce the impulsion and shock when the engine is being started. A brake means composed of brake hoof blocks and the wall of said wheel hub is provided in the device for the purpose of braking the wheel quickly and reliably. Two vertical side walls of the wheel hub are supported on the wheel axle shaft and on a boss ring axially protruding from the engine body fixed to the said shaft via bearings respectively, to assure a better load condition of the bearings and a stable and reliable support of the wheel. The said transmission units are disposed in a sealed box located inside the said hub, and can be lubricated with liquid lubricant, one side of the sealed box is fixed to the crankcase of the engine and the other side thereof is supported on the axially extending portion of a internal gear via a bearing, with sealing rings being provided there­ to. Channels are provided in the said boss ring to allow the insertion of oil inlet pipes, various actuating means and exhaust pipes, Besides, there are provided some openings on the wall of the wheel hub of the device to facilitate ventilation and maintenance. It is also appropriate to provide the hub wall with blades for introducing cooling air. The conversion between the manpower drive mode and the engine drive mode, the speed regulation of the engine drive mode, are integrally controlled by handles. For a better understanding of the nature and characteristics of the present invention, we are going to describe the embodiments according to the present invention in detail by way of the following accompanying drawings in which: Fig. 1 is an outline view of the drive device of the prior art; Fig. 2 is a schematic drawing of an embodiment of the present invention; Fig. 3 is a cross section view of the overrunning clutch located on the start gear of an embodiment of the present invention; Fig. 4 is an elevational view of the centrifugal clutch comprising a friction flying-weight and outer dish of an embodiment of the present invention; Fig. 5 is an elevational view of the overrunning clutch located on the internal gear of an embodiment of the present invention; Fig. 6 is a schematic view showing the arrangement of the engine and the transmission units in the wheel hub; Fig. 7 is a diagrammatic sketch of the brake of an embodi­ ment of the present invention. This embodiment according to the present invention (as shown in Fig. 2) is a device comprising engine and drive units, which is adapted mainly to bicycles or motor cycles. The engine in the said device is started through such a process to be described as follows: While rolling the vehicle wheel forward by manpower, lift the hand shank 1 on the handle bar of the vehicle in the direction shown by the arrow A in Fig. 2, pulling the lever 4 into motion through a wire 3 connected between the shank 1 and one end of the lever 4, the other end of the lever 4 being connected to the right end of a push rod 5, thus moving the push rod 5 in the direction shown by the arrow B in Fig. 2, so making the right part 9 of the tooth clutch to move leftward with the help of a pin 6 disposed at the radial direction of the push rod 5, thus causing the left part 8 of the gear clutch to mesh with the right part 9 thereof, said right part 9 being connected with the wheel hub via a spline 12, while the left part 8 of the gear clutch being fixed on the internal gear 23 which engages with the start gear 25 which is mounted on the crankshaft 30 of the engine 15 with an overrunning clutch 29 being disposed in between (as shown in Fig. 3), thus, the rotational movement of the wheel hub being finally transmitted to the crankshaft. Provide the engine with electricity and fuel supply in time. So the engine is started. The propulsion power of the engine is transmitted through the drive units to the wheel by the process to be described as follows: After the start of the engine 15, the crankshaft 30 brings the central portion 7 of the centrifugal friction clutch mounted thereon into fast rotation, causing the flying-­ weight 21 of the clutch to get into contact with the outer dish 22 (see Fig. 4), the friction therebetween causes the rotational movement of the dish 22, and consequently of the small gear 14 fixed therewith, gear 14 engages with the duplex gear 13 which transmits the rotational movement to the internal gear 23 by means of an idler 24. The disc portion of the internal gear 23 has an axially extending central sleeve, the outer wall of which is provided with a wedge ring 27 (as shown in Fig. 5). By means of rollers 28, the wedge ring 27 rotating in the direction shown by the arrow C in Fig. 5 transmits the propulsion to the hub 10. Since the engine body is firmly fixed to the frame 38 through both ends of the axle shaft 37, which prevents the drive device from being counter rotated, thus the wheel hub rotates forwardly under the propulsion. It is recommen­ ded to adopt spiral gears or herringbone gears in the above said drive units to get a stable and smooth power transmission. It is evident from the trilateral relation of the wedge ring 27, pin roller 28 and hub 10 that the rotation of the hub 10 alone in the C direction can hardly cause the rotation of the wedge ring 27, therefore there are hardly any interferences between the engine drive mode and the manpower drive mode. And in the case that the engine suffers a temporary overload, the manpower drive may be added to the wheel by means of pedals, chain and sprockets. Besides, when an excessive overload occurs (such as encoun­ tering sudden obstacle on the road surface, travelling up-hill along a road of an excessively big slope, etc.) the relative sliding between the flying-weight 21 and the outer dish 22 as well as between the rollers 28 and the hub 10 provide overload protection to the engine. The method to operate a bicycle equiped with a drive device according to the present invention may be as follows: 1. Before starting the engine, rotate the vehicle wheel by any suitable ways (such as pushing, or riding the well-known pedal, chain and sprocket assembly). Switch on the electrical circuit of the engine, pull the hand shank 1 located on the left handle bar in the direction shown by the arrow A in Fig. 2, rotate the handle 2 located on the right handle bar (i.e. opening the throttle valve). As a result, the engine being started. Rotate the handle 2 further to regulate the required fuel supply, then ride the vehicle forward. 2. The stop process of the vehicle mentioned above is as follows: First, cut off the electrical power by pressing down the button 16 to stop engine, then stop the vehicle after slipping for a certain distance; or hold the brake handle 17 (the same as on the common bikes or motorcycles) immediately after pressing down the button 16, to actuate the brake means composed of the brake cam 18, the support shaft 19 fixed in the box 31, the brake hoof blocks 20 and the wall of the wheel hub (see Fig.7), so as to make the two brake hoof blocks 20 expand outwardly in the hub 10, causing a sudden stop.

Claims: 1. A device for direct-driving of wheels adapted for various minivehicles, in particular for bicycles, motor-­ bikes or motor cycles, comprising a fixed wheel axle (37), a wheel hub (10) rotating about said wheel axle, an engine (15) and transmission units installed inside the said hub; the said device,characterized in that: said engine (15) and transmission units are substantially enclosed by the said hub (10), the engine crankshaft (30) being offset from the wheel axle (37) to a lower position therof, and being parallel thereto; the said transmission units comprise overrunning clutch means (29). 2. A device according to claim 1, characterized in that in said transmission units an engine starting mechanism is formed, said mechanism comprising a pusher (5), axially sliding spline means (12), over­ running clutch (29) and/or paw wheel and cam pawl, and a gear clutch (8/9), a half (9) of which is axially moveably mounted on the hub (10). 3. A device according to claim 1 or 2, characterized in that said wheel hub (10) has two sustantially vertical side walls aprovided with coaxial bearing seatings and is supported by bearings (35) on said wheel axle shaft and boss ring (36) protruding from the engine body fixed on the vehicle frame (38). 4. A device according to any of claims 1 to 3, characterized in that said transmission units have a centri­ fugal friction clutch (7/21/22) installed on the output shaft (30) of said engine (15). 5. A device according to any of claims 1 to 4, characterized in that said engine (15) is a two-stroke engine, wherein the top surface of the piston is formed of a spherical recess, a pair of lugs is provided at the inner side of said piston top, serving as a piston pin seating. 6. A device according to claim 5, characterized in that said engine piston is provided with an asymmetrical skirt portion, of which the parts near the axial line of the piston pin are cut off to form openings. 7. A device according to any of claims 4 to 6, characterized in that a magneto (32) and clutch mechanism (7/21/22) are respectively mounted at two ends of said engine crankshaft (30) the distance between the inner gyral plane of said magneto and the inner gyral plane of said clutch being smaller than the diameter of the cylinder bore. 8. A device according to any of claims 4 to 7, characterized in that said transmission units have a roller type overrunning clutch (29) mounted between the engine crankshaft (30) and the starting gear (25), the inner driven ring of which is formed by the cylindrical surface of the crankshaft (30), and the outer driving wedgering of which is formed on the inner peripheral surface of the starting gear (25). 9. A device according to any of claims 1 to 8, characterized in that said device has a brake means, composed of a pivot (19) fixed on the gear box for pivotably mounting at least one brake shoe (20) thereon, and a brake drum formed by the inner wall of the wheel hub (10). 10. A device according to any of claims 1 to 9, characterized in that inside the said wheel hub (10) said transmission units are substantially enclosed by a sealed case, the said case is fixed and sealed at one side thereof to the crank case, and is supported and sealed at another side thereof on an internal gear case via bearing and seal rings (34). 11. A device according to any of claims 3 to 10, characterized in that the left side wall of said hub (10) is supported via a bearing (35) on said boss ring (36) having inner tunnel for introducing various pipe lines and actuating means. 12. A device according to any of claims 1 to 11, characterized in that the gear members used in said trans­ mission units are spiral tooth gears or herringbone tooth gears. 13. A device according to any of claims 3 to 12, characterized in that the walls of the said hub are provided with holes for maintaining and ventilating, and with detachable coverplates. 14. A device for direct-driving of wheels as in any of the preceding claims, characterized in that an overrunning clutch means (29) is disposed between the last stage gear of the transmission units and the wheel hub (10), the driving ring of the said clutch means is fixed on the said last stage gear and the driven ring of the clutch is fixed on or integrally formed with the inner wall of the hub.

Inventors: ZHEN, WANG QI
Applicants: ZHEN, WANG QI
Application year: 1986
Main classification: B62M7
IPC codes: B62M7, B62M23, B60K7