EP0298791B1 - Starting device for a two-wheeled motor vehicle - Google Patents

Description

The subject of the present invention is a starting device for a two-wheel motorized vehicle, comprising pulley and belt transmission means between a shaft of a starting pedal and a crankshaft of the engine. The pulley and belt system consists of a drive pulley secured to the crankshaft and a take-up pulley mounted on a tubular shaft capable of driving the drive wheel by means of a clutch and a shaft placed in the tubular shaft.

We know two-wheeled vehicles with a start pedal, commonly called "kick" pedal. To obtain a sufficient multiplication ratio between the shaft carrying this starter pedal and the engine crankshaft, it is generally necessary to provide an intermediate shaft so as to produce the transmission between the shaft of the starter pedal and the crankshaft by means of two pairs of multiplying gears. This arrangement complicates the transmission and increases its size.

It is also known to carry out the transmission by a single pair of gears, but the multiplication ratio obtained is then relatively low and obliges to provide on the shaft of the starter pedal a pinion of a large diameter, which increases clutter.

In addition, if the engine is mounted oscillating on the frame, which is often the case, it is necessary that the assembly of the intermediate shaft can move with the engine, which also complicates the device.

Other arrangements are also known in which the actuation of the starter pedal controls a decompression valve in the engine's combustion chamber, to make it easier to start the engine. Finally, document EP-A 0 157 880 discloses a starting device in accordance with the preamble of claim 1.

The object of the invention is to provide a device which makes it possible to start the engine of a two-wheeled vehicle from a starting pedal, eliminating the above drawbacks, while having a sufficient multiplication ratio between the shaft of this starter pedal and the engine crankshaft.

According to the invention, the starting device conforms to the characterizing part of claim 1 or 3.

The invention also has other characteristics, according to claims 2 and 4 to 10.

• la Figure 1 est une vue en élévation latérale partielle de l'ensemble moteur et dispositif de démarrage d'un véhicule à deux roues visé par l'invention.
• la Figure 2 est une vue de dessus avec coupe partielle horizontale d'un premier mode de réalisation du dispositif de démarrage pour véhicule motorisé à deux roues selon l'invention, l'arbre de la pédale de démarrage étant en position débrayée;
• la Figure 3 est une vue analogue à la Figure 2 montrant le pignon de l'arbre de la pédale de démarrage en prise avec un pignon correspondant d'un second arbre portant une poulie réceptrice;
• les Figures 4 et 5 sont des vues latérales simplifiées illustrant deux formes de réalisation d'un système permettant de bloquer le moteur lors de son démarrage, dans un véhicule dont le moteur est monté oscillant sur le cadre;
• les Figures 6 et 7 sont des vues simplifiées respectivement en élévation latérale et de dessus d'une autre forme de réalisation dans laquelle le dispositif de démarrage est équipé d'un système permettant d'augmenter la tension de la courroie de transmission lors du démarrage, le moteur étant monté oscillant sur le chassis du véhicule;
• la Figure 8 est une vue schématique d'un système de commande de la décompression du moteur lors de son démarrage, pouvant être ajouté au dispositif de démarrage des Figures précédentes;
• La Figure 9 est une vue en élévation latérale d'une forme de réalisation industrielle du système de commande de décompression du moteur;
• les Figures 10 à 14 sont des vues analogues à la Figure 9 et à échelle réduite, illustrant les phases successives du fonctionnement du système de commande de décompression lors du démarrage du moteur.

Other features and advantages of the invention will appear during the description which follows, given with reference to the appended drawings which illustrate several embodiments thereof by way of non-limiting examples:

• Figure 1 is a partial side elevational view of the engine and starting device of a two-wheeled vehicle covered by the invention.
• Figure 2 is a top view with partial horizontal section of a first embodiment of the starting device for a two-wheel motorized vehicle according to the invention, the shaft of the starting pedal being in the disengaged position;
• Figure 3 is a view similar to Figure 2 showing the pinion of the starter pedal shaft engaged with a corresponding pinion of a second shaft carrying a take-up pulley;
• Figures 4 and 5 are simplified side views illustrating two embodiments of a system for blocking the engine during startup, in a vehicle whose engine is mounted oscillating on the frame;
• FIGS. 6 and 7 are simplified views respectively in side elevation and from above of another embodiment in which the starting device is equipped with a system making it possible to increase the tension of the transmission belt during starting, the engine being mounted oscillating on the chassis of the vehicle;
• Figure 8 is a schematic view of a system for controlling the decompression of the engine when it starts, which can be added to the starting device of the previous Figures;
• Figure 9 is a side elevational view of an industrial embodiment of the engine decompression control system;
• Figures 10 to 14 are views similar to Figure 9 and on a reduced scale, illustrating the successive phases of the operation of the decompression control system when starting the engine.

The two-wheeled motor vehicle targeted by the invention comprises (FIG. 1 to 3) an engine 3 with an exhaust pipe P, a shaft 10 for driving a pinion and a driving wheel chain (these elements not being shown), and a transmission between a crankshaft 2 of the engine 3 and the shaft 10.

This transmission comprises a driving pulley 7 mounted on the crankshaft 2, a receiving pulley 7 mounted on a tubular shaft 5 containing the drive shaft 10, a belt 8 connecting the pulleys 7 and 4, and a clutch 20 capable of transmit to the shaft 10, the rotation of the receiving pulley 4 in a manner known per se.

The pulleys 4 and 7 are dimensioned so as to ensure a sufficient multiplication ratio between the shaft 6 of the starter pedal and the crankshaft 2, the receiving pulley 4 having for this purpose a diameter much greater than that of the driving pulley 7 .

The starting device comprises a shaft 6 parallel to the drive shaft 10, and a starting pedal 21 (“kick” pedal) making it possible to drive the shaft 6 in rotation.

A pair of gears 9, 11 is arranged between the shaft 6 of the pedal and the shaft 5 of the receiving pulley 4 in order to transmit the rotation of the shaft 6 to the shaft 5 and to the pulley 4. The pinion 9 is fixed on the end of the shaft 6 so as to be offset axially with respect to the pinion 11 of the shaft 5 when the device is at rest (Figure 2), position in which the pinion 9 and the shaft 6 are constantly stressed, in a manner known per se, by a return spring 12 surrounding the shaft 6.

When the starter pedal 21 is actuated, a device known per se and not shown axially displaces the shaft 6 so that its pinion 9 comes to mesh with the pinion 11, by which the shaft 5 and the receiving pulley 4 are driven rotating (Figure 3). The belt 8 then rotates the pulley 7 and the crankshaft 2. As soon as the pedal 21 is released, the pinion 9 is uncoupled from the pinion 11, the motor 3 driving the shaft 10 via the belt 8, pulleys 7, 4 and clutch 20.

Figures 4 and 5 illustrate two modes of embodiment of the invention in which it is applied to a vehicle whose engine 3 and its driving pulley 7 are mounted on a support 13 oscillating around an axis 14 on the frame or chassis 15 of the vehicle. A spring 16 fixed by its ends to the support 13 and to the chassis 15 constantly stresses the support 13 and consequently the drive pulley 7, in order to maintain a sufficient tension of the belt 8. Means are provided for blocking the motor 3 and the pulley 7 in their normal angular position, in order to maintain the tension of the belt 8 at a sufficient value during the starting of the engine 3.

In the embodiment of FIG. 4, these means comprise a cam 17 mounted oscillating on the chassis 15 on either side of an axis 18 and which is linked by a rod 19 to the receiving pulley 4. The cam 17 , which can be smooth or notched, is urged, at its end remote from the support 13, by an elastic member 23 fixed to the chassis 15, so that in the inactive position, the cam 17 is released relative to a stop 24 integral with the oscillating support 13.

The actuation of the starting pedal 21 in the direction of the arrow F rotates in the same direction the receiving pulley 4, which in turn drives by the rod 19 the cam 17, which switches around the axis 18 in coming to be placed between the latter and the stop 24 (position shown in FIG. 4). In this position, the cam 17 opposes the tilting of the support 13 and consequently of the motor 3 and of the pulley 7 during startup, and therefore prevents the pulley 7 from approaching the receiving pulley 4. As a result, the belt tension 8 is maintained during start-up, while in the absence of the cam 17 and its control means, the tension of the belt 8 would decrease due to the fact that the force exerted on the starter pedal 21 is transmitted to the belt 8 and would cause the engine assembly (3,7) to move back towards the pulley 4, reducing the tension of the belt 8 and causing it to slip.

The return of the pedal 21 to its initial position automatically brings the cam 17 back to its starting position, excamotated with respect to the stop 24. The distance between the motor 3 and the pulley 4 is then normally maintained by the spring 16.

In the variant of FIG. 5, the means for blocking the oscillating support 13 when the engine starts include a connecting rod 25 linked to the engine 3 at one of its ends and slidably mounted on the chassis 15 at its opposite end. To this end, a buttonhole 26 is formed in this second end, and a finger 27 secured to the chassis 15, engaged in this buttonhole 26, allows displacements of the connecting rod 25 and of the drive pulley 7 relative to the chassis 15. A cam 28 articulated on the chassis 15 is urged by a compression spring 29, one end of which is fixed to the chassis 15, so as to be retracted with respect to a stop 31 provided on the connecting rod 25, when the start pedal 21 is at rest. In this rest position, in fact, an end portion 21a of the pedal 21 acts on an associated end of the cam 28 so as to keep the latter released relative to the connecting rod 25 and the spring 29 compressed.

When the pedal 21 is actuated (arrow F), its end 21a releases the cam 28 which then switches under the action of the spring 29 to come into place in its position illustrated in FIG. 5, where it is at contact of the stop 31. The connecting rod 25 and the cam 28 are then in the extension of one another between the axes of rotation of the pulleys 4 and 7, which ensures the automatic blocking of the pulley 7 and of the motor 3 in their initial position before starting.

Any reduction in the distance between the pulley 7 and the pulley 4 is thus prevented, the tension of the belt 8 is maintained and any risk of slipping thereof is avoided. The return to its initial position of the starting pedal 21 causes, via the end 21a, a separation of the cam 28 relative to the connecting rod 25, so that the cam 28 returns to its initial position by compressing the spring 29. The buttonhole 26 of the connecting rod 25 allows variations in the distance between the pulleys 4 and 7, which makes it possible to take into account the length and wear of the belt, as well as the dispersion of the dimensions of engine manufacturing or reverse in the case of a variator transmission.

In the two embodiments of FIGS. 4 and 5, the cams 17, 28 can be smooth or notched, and automatically block the driving pulley 7 and the motor 3 in their initial angular position during start-up, whatever the distance between the pulley drive and take-up pulley 4.

In the embodiment of Figures 6 and 7, the motor 3 and the drive pulley 7 are also mounted on a support 13 oscillating around the axis 14 on the chassis 15, and means are provided for increasing the tension of the belt 8 during engine start 3.

To this end in this embodiment, a rod 32 is connected to a cam 33 of the shaft 30 of the start pedal 21, and there is provided a spring 34 with two branches 35.36 in V whose ends are respectively fixed to the support 13 and to the rod 32. The branch 36 is supported on the frame 15 when the system starting 21, 33 is at rest (position shown in solid lines in Figure 7), the spacing between the branches 35 and 36 then being maximum. At start-up, when the pedal 21 switches, the cam 33 secured to the shaft 30 pushes the rod 32 towards the motor 3, so that the branch 36 is brought closer to the branch 35 by this movement of the rod 32, to occupy position 36a (in phantom). This displacement of the branch 36 towards the branch 35 causes an increase in the compression of the spring 34 and consequently an increase in the tension of the belt 8, which eliminates any risk of it slipping during the start-up phase. The return of the starting system 21, 30, 33 to its initial position returns the rod 32 and the branch 36 to their starting position.

FIG. 8 schematically shows a first embodiment of means for decompressing the engine when it starts, which can be added to the devices described above.

In this embodiment, the decompression means comprise a cam 37 integral with the starter pedal 21 and able to cooperate with a lever 38 coupled to a cable 39 for controlling a valve 41 of a decompressor 42, during the actuation of the pedal 21. A spring 43 automatically returns the valve 41 to its initial position when the starter pedal 21 returns to its starting position, and likewise a spring 44 associated with the cable 39 and bearing on the lever 38 bring cable 39 back to its initial position.

When the pedal 21 is actuated, the cam 37 switches the lever 38 coupled to the cable 39 of the decompressor 42, so that the start of the stroke of the starting system ensures the decompression of the engine. Then, at the end of travel of the pedal 21, the cam 37 no longer acts on the lever 38, while the starting system ensures the starting of the engine.

The cable 39 is connected, beyond the decompressor 42, to a manual handle 40 for controlling the decompressor 42. This handle makes it possible to act on the decompressor 42 manually to stop the engine or to start it.

In the embodiment illustrated in FIG. 9, the means for decompressing the engine are constituted as follows:

An automatic lever 45 is articulated around an axis 46 fixed on a support 47 and secured to the end of the cable 48 for controlling the decompressor. A pawl 49 is articulated on the automatic lever 45 around an axis 55 and returned to a rest position by a spring 51 whose ends are respectively fixed to the pawl 49 and to a manual lever 52 also articulated on the axis 46, this lever 52 being connected to a cable 53 for manual decompression control.

The pawl 49 has a terminal spout 49a adapted to be able to cooperate with a cam stop 56 integral in rotation with the starter pedal (not shown), the shaft 6 and the return spring 12 of which can be seen. The automatic lever 45 is provided with a stop 57 on which the manual lever 52 rests when the device is at rest (FIG. 9).

This decompression system can operate either automatically or manually.

Automatic operation (Figures 10 to 14)

The action of the foot on the kick pedal rotates the cam stop 56 integral with the pedal and its shaft 6, in the direction of arrow G in Figure 10. The projecting part 56a of the cam stop 56 comes then in contact with the end 49a of the pawl 49, which by means of its stop 49b rotates the automatic lever 45 around its axis 46, the aforementioned parts then coming into the position of FIG. 11. During its tilting, the lever 45 therefore exerts traction on the cable 48 for controlling the decompression of the engine.

From a certain angle of rotation of the kick pedal, the active part 56a of the cam stopper 56 exceeds the pawl 49 (Figure 12) and the lever 45 and the pawl 49 return to their initial position, under the action in particular of the spring of the decompressor valve 43 (Figure 8) via the decompressor cable 48.

The rotation of the kick pedal continues until its end, then the return spring 12 brings it back to its starting position. During this return stroke, the projecting part 56a of the cam stop 56 causes the pawl 49 (Figure 13) to toggle which is then returned to its previous position by the spring 51 (Figure 10).

Manual operation (Figure 14):

Manual action on the lever 40 (Figure 8) of the decompressor on the handle causes traction on the cable 53 and rotation of the manual lever 52 around the axis 46.

The lever 52 then exerts on the stop 57 a thrust which drives the automatic lever 45 in rotation, also around the axis 46, this lever 45 then exerting traction on the decompressor cable 48.

When the traction on the manual control cable 53 ceases, the levers 52 and 45 as well as the pawl 49 return to their initial position in FIG. 9.

The invention has the advantage of using, for the starting device, the transmission means existing on the vehicle (pulleys 4 and 7 and belt 8). This reduces the size of the starting system while ensuring, thanks to the difference in the diameters of the driving and receiving pulleys 7, a sufficient multiplication ratio between the shaft 6 of the starting pedal 21 and the crankshaft 2.

Furthermore, the decompression means illustrated in FIGS. 8 to 14, facilitate starting the engine by allowing the decompression of the combustion chamber, the combination of these decompression means with the starting system of FIGS. 1 to 3 being particularly advantageous.

Finally, the embodiments of FIGS. 4 to 7, combined with that of FIGS. 1 to 3, have the advantage of also facilitating the starting of the motor 3 by avoiding any slippage of the belt 8.

Claims (10)

1. A starting device for a two wheeled motor vehicle, including, between an engine (3) and a drive shaft (10) of a driving wheel, a pulley (4, 7) and belt (8) transmission, as well as means provided between a shaft (6) of a starting pedal (21) and a crankshaft (2) of the engine (3), said transmission being formed by a driving pulley (7) rigidly connected to the crankshaft (2) and by a driven pulley (4) mounted on a shaft (5) which is able to drive the driving wheel by way of a clutch (20) and a drive shaft (10), in which a geared connection (9, 11) is disposed between the shaft (6) of the pedal (21) and the shaft (5) of the driven pulley (4) in order to transmit the rotation of the first shaft (6) to the second (5), which itself drives the driven pulley (4) and the driving pulley (7) associated with the crankshaft (2) to start the engine (3), this latter and its driving pulley (7) being mounted on a swinging support (13) on the frame (15) of the vehicle, characterised in that it includes resilient means interposed between the engine (3) and the starting pedal (21) to increase the tension of the belt (8) during starting of the engine.

2. A device according to Claim 1, characterised in that said resilient means has a rod (32) connected to the shaft (30) of the starting pedal (21), a spring (34) having two arms (35, 36) forming a V, of which the ends are fixed respectively to the support (13) of the engine and to the rod (32), the arm (36) fixed to the rod (32) bearing on the frame (15) when the starting system is at rest and being brought nearer to the other arm (35) by the displacement of the rod (32) driven by the rotation of the shaft (30, 33) of the pedal (21) upon starting, which causes an increase in the tension of the belt (8) when starting takes place.

3. A starting device for a two wheeled motor vehicle, including, between an engine (3) and a drive shaft (10) of a driving wheel, a pulley (4, 7) and belt (8) transmission, as well as means provided between a shaft (6) of a starting pedal (21) and a crankshaft (2) of the engine (3), said transmission being formed by a driving pulley (7) rigidly connected to the crankshaft (2) and by a driven pulley (4) mounted on a shaft (5) which is able to drive the driving wheel by way of a clutch (20) and a drive shaft (10), in which a geared connection (9, 11) is disposed between the shaft (6) of the pedal (21) and the shaft (5) of the driven pulley (4) in order to transmit the rotation of the first shaft (6) to the second (5), which itself drives the driven pulley (4) and the driving pulley (7) associated with the crankshaft (2) to start the engine (3), this latter and its driving pulley (7) being mounted on a swinging support (13) on the frame (15) of the vehicle, and a spring (16) fixed by its ends to the support (13) and to the frame (15) constantly urges the support in such a way as to maintain a sufficient tension in the belt, characterised in that means are provided for angularly locking the engine (3) in order to maintain the tension of the belt (8) during starting of the engine.

4. A device according to Claim 3, characterised in that said means have a cam (17) swingably mounted on the frame (15), connected by a rod (19) to the driven pulley (4), urged by a resilient element (23) fixed to the frame (15) in such a way that, in the inactive position, said cam is disengaged with respect to an abutment (24) rigid with the swinging support (13) of the engine, and that operation of the starting pedal (21) causes the cam (17) to swing into a position in which it cooperates with the abutment (24) to prevent the engine (3) and the pulley (7) of the crankshaft to come closer to the driven pulley (4), the return to its initial position of the starting pedal (21) automatically returning the cam (17) to its starting position retracted with respect to the abutment (24).

5. A device according to Claim 3, characterised in that said means include a tie-rod (25) connected to the engine (3) at one of its ends and slidably mounted on the frame (15) at its opposite end, and a cam (28) pivoted on the frame (15), held disengaged from the tie-rod (25) by the starting system when the latter is at rest, this cam (28) being resiliently driven into a position in which it locks the tie-rod (25) when it is freed by operation of the starting system (21, 21a), and the return of the starting pedal (21) to its initial position causing the cam (28) to swing, returning it to its disengaged position with respect to the tie-rod (25).

6. A device according to one of Claims 1 to 5, characterised in that it includes, in addition, means for decompression of the engine (3) during starting.

7. A device according to Claim 6, characterised in that said decompression means include a cam (37) rigidly connected to the starting pedal (21) and adapted to cooperate with a lever (38) coupled to a cable (39) controlling a valve (41) of a decompressor (42) during operation of the starting pedal (21), resilient means (44, 43) then automatically returning the lever (38) and the cable (39) on the one hand, and the valve (41) on the other hand, to their initial positions.

8. A device according to Claim 7, characterised in that the cable (39) is connected, beyond the decompressor (42), to a manual control-lever (40) for the latter.

9. A device according to Claim 6, characterised in that said means include an automatic lever (45) pivoted about a shaft (46) fixed to a support (47) and rigidly connected to the end of the decompressor cable (48), a catch (49) pivoted on said lever (45), returned to a rest position by a spring (51) and adapted to be able to cooperate with an abutment-cam (56, 56a) fast for rotation with the starting pedal (21) in such a way that the rotation of the pedal automatically causes the simultaneous rotation of the catch (49) and the lever (45), this latter then exerting a pull on the cable (48) of the decompressor.

10. A device according to Claim 9, characterised in that it has, in addition, a lever (52) connected to a cable (53) for manually controlling the decompression, pivoted on the support (47) about the same shaft (46) as the automatic lever (45), and on which is fixed one end of the return spring (51) of the catch (49), and the automatic lever (45) is provided with a bearing abutment (57) for the manual lever (52) arranged in such a way that a pull on the cable (53) for manually controlling the decompression causes the manual lever (52) to swing together with the automatic lever (45), as a result of the manual lever bearing on the abutment (57) rigid with the automatic lever (45).

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