FR2461610A1 - Car with secondary drive - has motor driving rear wheels which disengages at certain speed and petrol engine driving front wheels - Google Patents

Abstract

The vehicle has a forward mounted primary petrol engine operatively engaged with the front axle and its wheels. The vehicle also has a rear mounted second motor driving the rear axle which is normally a dead axle. The second motor is an electric motor operable in two directions but it may be a hydraulic pump/moto. The second motor, which may be driven by the primary motor or from an independent power source such as a battery, is operated by the vehicle operator and automatically disengageable upon reaching a predetermined speed.

Description

The invention relates to vehicles and more particularly to vehicles comprising both a primary engine and an auxiliary engine.

 It is well known that conventional vehicles such as passenger cars are frequently stuck in mud, in snow or on ice when the drive wheels, frequently the rear wheels, lose their grip. The growing success of small passenger cars has made grip problems in such adverse conditions more common. Medium and small cars are specially designed to be light and therefore they have grip problems. In addition, they are generally fitted with tires and small wheels which, as is well known, have a resistance of Relatively high turnover. The increased use of plastics and other lightweight materials in these and other vehicles has made these grip problems even more common.

 Classic two-wheel drive passenger cars are particularly exposed to the risk of blockage when traveling on roads with unfavorable conditions. It has been known for a long time that vehicles with four-wheel drive constantly, for example military vehicles or leisure vehicles, are particularly suitable for traveling on roads having unfavorable conditions. These vehicles have front and rear axles controlled by a single source of motive power, for example a gasoline engine. We have also designed vehicles whose four wheels can be momentarily driven. These vehicles, the wheel locks or clutches are selectively engaged by hand or automatically, in order to transform the vehicle of the two-wheel drive type into a four-wheel drive type. Although vehicles whose four wheels are constantly or momentarily driven have proven to be very satisfactory in particular situations, the large control mechanisms which they use are generally not adaptable, from the point of view of dimensions and weight, to cars medium and small cars currently popular.

 The invention relates to a vehicle comprising a light auxiliary control device, and in particular a vehicle comprising a main motor and an auxiliary motor and capable of being selectively driven by means of two axles.

 The invention therefore relates to a vehicle comprising a main motor for controlling a first axle which drives a first wheel, and a secondary motor controlling a second axle which can selectively engage with a second wheel. The secondary motor is preferably a reversible electric motor. It can be started manually by the driver of the vehicle and it can be disengaged automatically when the vehicle reaches a predetermined speed. The secondary motor can be driven by the main motor, or by an independent source of energy, for example a storage battery. The second axle is only load-bearing when the secondary engine is stopped. The second wheel therefore comprises a free wheel device allowing the second axle to rotate preferably in both directions.

The invention will be described in more detail with reference to the accompanying drawings by way of non-limiting examples and in which
- Figure 1 is a perspective view of a vehicle comprising the auxiliary control device according to the invention, a part of this vehicle being repre-sent with cutaway to show chassis elements;
- Figure 2 -is a rear view showing the rear axle and wheel assembly of the vehicle shown in Figure 1;
- Figure 3 is a partial longitudinal soup of the extreme assembly carrying the right rear wheel of the axle shown in Figure 2; and
- Figure 4 is a diagram of the electrical circuit of the auxiliary control device according to the invention.

FIG. 1 represents a small passenger car 10 comprising a chassis 12 on which a body 14 is fixed. This vehicle 10 comprises a main engine 20 mounted at the front, namely a petrol engine in the preferred embodiment described. The energy required to start the motor 20 is supplied by a 12 volt battery 18. Most of the electrical circuit used for starting the engine 20, for example the starter and the associated wiring, is not shown in FIG. 1, since it is well known to those skilled in the art. An electric generator 19, driven by the motor 20, is intended to recharge the battery 18 via a voltage regulator 21 and to supply electrical energy to the various electrical accessories of the vehicle, for example a radio receiver, a device heating, fires, etc.

 In the preferred embodiment described, a manual transmission 22 is connected to the output shaft (not shown) of the engine. It should however be noted that the invention can be easily adapted to a vehicle with automatic transmission. A transmission output shaft 23 runs down from the bottom of the transmission 22 and leads to a differential 24 at right angles. Right and left front half-axles 25 and 26 are mechanically connected to the transmission output shaft 23 by means of the differential 24 and carry front drive wheels 27. The transmission 22 makes it possible to drive the half-axles 25 and 26 in the forward and reverse directions, in a manner well known to those skilled in the art.

The steering mechanism controlling the front wheels 27 is not shown in Figure 1, because it is also well known.

As shown more clearly in FIG. 2, the vehicle 10 comprises a rear axle assembly 34 which can be selectively controlled and housed in a casing 36 which is disposed between the right and left rear wheels 37 and 37 '.

The rear axle housing 36 is bent upwards, near the center of the vehicle, in order to increase the ground clearance. It is however obvious that the invention also applies to a straight axle. The right side of the assembly 34 comprises shafts 35, 48 and 50 constituting the right half-axle (FIG. 3) and connected end to end by universal joints 46 and 47. The left side of the assembly 34 comprises a series identical shaft, including a shaft 35 ', the operation of the two sides of the assembly 34 being the same.

 A secondary electric motor 40 is rigidly fixed to the rear part of the chassis 12, above the rear axle assembly 34, by means of flanges 39. The chassis 12 is connected to the housing 36 of the rear axle by springs rear 33 and 33 'which attenuate the shocks transmitted to the chassis and to the secondary engine 40 by the poor condition of the roadway.

 A telescopic sliding shaft 42 (see also in FIG. 1) starts from the electric motor 40 and leads to a gearbox 44 for return at a right angle. This shaft 42 makes it possible to follow all the variations in deviation between the motor 40 and the casing 36 of the axle, for example those due to the poor condition of the roadway. The shaft 42 is preferably designed to execute telescopic movements over the distance required to follow the expected movements of the axle.

 The gearbox 44 includes a housing 45 made in one piece with the housing 36 of the axle.

It contains a worm wheel 41, rigidly wedged on the half-shafts 35 and 35 of the axle. This wheel 41 is therefore designed to drive both the right and left wheels 37 and 37t, as described below. The box 44 also contains an endless screw 43 which is engaged with the wheel 41, which is fixed to the telescopic shaft 42 coming from the motor 40 and which is driven by the latter.

It should be noted that other types of transmission systems can "@ easily adapted in place of the transmission box 44. For example, other types of gears such as a spiral, helical gear or planetary, can be used, as well as belt or chain transmissions, alone or in combination with a gear. The worm and wheel gear described is currently preferred because of its high torque ratio
When the electric motor 40 is stopped, the whole of the axle assembly 34, including the shafts 35, 35 ', 48 and 50, is fixed. In other words, the assembly 34 normally constitutes a “dead” axle. The extreme assemblies associated with the rear wheel can therefore be designed to allow free rotation of the rear wheels 37 and 37 ′ when the rear axle is fixed.

As shown in Figure 3, the shaft 50 of the right half-axle has, near its outer end section, a thread 52 of right hand pitch. The extreme wheel assembly 53 comprises a fixed element 54 which is rigidly connected to the axle housing 36 and which contains a set of bearings 49 ensuring the radial alignment of the shaft 50.

 A threaded input coupling element 55, made of steel, is screwed onto the threaded outer section of the shaft 50. This input coupling element 55 has two frustoconical surfaces 59 and 60 whose tapers move away one from the other. The fixed element 54 has an annular projection 51 extending axially outwards and towards the wheel 37. An annular coupling spring 56 is rigidly fixed on the projection 51 and can slide on an annular projection 57 extending axially inwards of the input element 55 of the coupling.

A two-piece coupling output member is rigidly connected to the right rear wheel in a manner well known to those skilled in the art, for example by means of bolts. The parts 58 and 68 of this outlet element are rigidly fixed to each other by an elastic ring 78. These parts 58 and 68 delimit a cavity 61 in which the input element 55 of the coupling is housed. The cavity 61 of the outlet element is defined in part by two frustoconical mating surfaces}, namely a surface 69 presented by the part 68 and a surface 70 presented by the part 58. These surfaces 69 and 70 are intended to rub against the surfaces 59 and 60, respectively, of the input element. The output coupling element consists of two parts 58 and 68 in order to allow the introduction of the input coupling element 55 in the cavity 61. The part 58 of the output element also houses a bearing 71 ensuring the radial alignment of the shaft 50. The casing 36 contains a bearing 79 ensuring the radial alignment of the element d output coupling 58.

 When the shaft 50 is driven in the forward direction (indicated by the arrow 63 in FIG. 3), the input coupling element 55 is held in the fixed position, without turning, by the friction spring 56. This element 55 therefore moves by screwing outwards (to the right in the orientation of FIG. 3) on the input shaft 50, that is to say towards the wheel 37, until that the surface 60 comes to rub against the surface 70 of the outlet coupling element. At this time, the input coupling element 55 is blocked between the input shaft 50 and the part 58 of the output coupling element. The blockage between these two members lasts as long as the output coupling element 58 continues to drive the wheel 37. Under these conditions, the force of the friction spring is overcome by the driving force and the coupling element. input rotates with the shaft 50 and with the wheel 37.

If the driving force applied by the shaft 50 comes to stop, for example following the stopping of the auxiliary motor 40 or a rotation of the wheel 37 at a speed greater than that of the rotation of the input shaft 50, the wheel 37 can rotate freely relative to the input shaft 50. When this wheel 37 rotates faster than the shaft 50, the output coupling element 58 rotates the input coupling element 55 in the forward direction 63 relative to the shaft 50 due to the 'engagement by friction between the coupling elements 55 and 58. The output element 58 therefore displaces the input element 55 axially inwards on the threaded shaft 50, in order to separate the coupling surfaces 60 and 70 from each other.

 When the shaft 50 continues to rotate, the friction spring 56 prevents the input coupling element 55 from rotating, which causes its direction of displacement to reverse and its axial movement towards the outside and towards the wheel 37. I1 results in its re-engagement with the output coupling element 58. If the speed at which the input shaft 50 rotates is less than that of the output coupling member 58, the input member 55 bounces and moves away from the engagement position each time the friction spring 56 and the shaft 50 teneentde bring the surfaces 60 and 70 against each other. If the wheel 37 slows down to a speed lower than that of the shaft 50, the surfaces 60 and 70 d 'couplings come into contact again, as described above, and the wheel is again driven.

 When the auxiliary motor is stopped for any reason, the input shaft 50 also stops and the wheel 37 rotates freely relative to this shaft 50, as described above. By turning, the wheel 37 releases the input coupling element 55 from the output coupling element 58. Since the shaft 50 is stopped, the friction spring 56 maintains the coupling element 55 between the surfaces 69 and 70 of the outlet element 58 and no impact occurs between the elements 55 and 58.

 A rotation in the opposite direction of the shaft 50 causes the surfaces 59 and 69 to come into contact and, consequently, the drive of the wheel 37 in the direction corresponding to the reverse gear. Freewheeling in this direction is obtained in the same way as in the forward direction.

 It should be noted that the wheel end assemblies work, whether the pitch of the threading of the end shafts such as the shaft 50 is to the right or to the left, this pitch having the sole effect of determining the surfaces of the coupling. coming into contact with each other in forward and reverse. It should also be noted that the end assemblies 53 and 53 'are essentially identical and that they simultaneously drive the wheels 37 and 37', respectively. Given the freewheeling possibilities of the assemblies 53 and 53 ′, no differential gear is necessary, since the slowest wheel is always driven while the fastest wheel is coasting.

The preferred circuit for the auxiliary motor comprises a device releasing the input coupling element 55 from the output coupling element 58 or 68 when the auxiliary motor 40 is stopped. The coupling elements are separated by momentary rotation of the end shaft 50 in the opposite direction to that of the drive. This brief rotation, for example over a quarter turn, in the opposite direction ensures the release of the input coupling element 55 which thus emerges from its friction blocking with the output coupling element. This blockage would risk driving the entire mechanism back, which could cause damage to the latter. The preferred electrical circuit for controlling this clearance will be described in detail below.

 As shown in FIG. 1, the auxiliary electric motor 40 is electrically and directly connected to the battery 18. It is therefore possible to start this auxiliary motor 40 for short periods by means of the battery 18, without the motor 20 does not rotate.

An on / off control switch 66 for the auxiliary motor is mounted on an electric line 62 connected to the auxiliary motor, and this switch is suitably mounted on the driving console of the vehicle.

 It is sufficient, for most of the situations envisaged, that the battery 18 can move the vehicle at a speed of approximately 8 km / h over a distance of up to 200 to 300 m, before requiring recharging. However, if the motor 20 is running, the generator 19 continuously recharges the battery 18 via the voltage regulator 21 and the electric motor 40 is in fact controlled by the main motor. As a variant, the electric motor 40 can be electrically connected directly to the voltage regulator 21 and to the generator 19 by the cables 64 shown in phantom in Figure 1.

In this variant, the secondary motor 40 can only be started when the main motor 20 is operating.

 In the preferred embodiment described, the auxiliary motor 40 is an electric motor; reversible series, with auxiliary starting winding, with direct current, operating at a voltage of 12 volts.

 It can be started in the forward or reverse direction.

 It is controlled by a relay logic circuit comprising a number of relays, switches, diodes, capacitors and indicator lights. A preferred electrical circuit for implementing the advantageous form of the auxiliary motor device according to the invention is shown in FIG. 4.

In FIG. 4, all the relays are represented in the form of coils and are indicated in "R" (for example Rl, R-2, etc.). Each relay controls a corresponding set of contacts indicated in CR (for example
CR-1, CR-2, etc.).

 The electric motor 40 is supplied with energy by the positive terminal of a common 12-volt battery.

To start the auxiliary motor 40, a momentary push-button IM is pressed to close the circuit. The VM light is thus lit, indicating that the device is on. Battery current flows through a relay R-1, the normally open contact of which CR-1 closes, thus allowing battery current to pass through relays R-2 and R-3. The normally open contact CR-2 therefore closes and thus short-circuits the IM switch after its spring has returned it to its normal open position. The auxiliary device can then operate without the IM switch being closed.The current flowing through relay R-3 at the same time causes the normally open contact to close
CR-3 and the opening of the normally closed contact CR-3 which has the effect of charging a switching capacitor and jolts CCA. Before the current reaches the motor 40, it must pass by a stop switch IA and by an over-speed switch of the motor ISM, these two switches being normally closed, so as to reach the normally open contact CR-9. This CR-9 contact is closed by the R-9 relay when the latter is excited by the current flowing from the battery in an ITE excessive temperature switch. This switch is normally closed unless the motor 40 has overheated. Current must also pass through a normally closed contact CR-5 which can be opened by the relay R-5 if the vehicle's brake pedal is depressed, or by the closing of a clutch switch lE. In a vehicle with automatic transmission, it is obvious that the clutch switch is removed.

The circuit followed by the current to reach the auxiliary motor 40 must pass through an acceleration switch IAC which is closed by a light depressing of the accelerator pedal. Closing this switch allows current to reach a normally open contact CR-10. R-10 relay closes contact
CR-10 when the IAL ignition switch is closed by the driver of the vehicle when he turns the ignition key to the on position.

When all the switches and contacts mentioned above are closed, the current can reach the contact CR-6 which is normally closed and the contact
CR-6 which is normally open. When the electric motor 40 is started in the forward direction, the ignition
CR-6 remains closed so that current flows through diodes Dl and D-2. The current flowing through the diode Dl charges a backward capacitor CAR. The current passing through the diode D-2 excites a relay R-8 which closes the contact CR-8. Current can then pass through a relay MR-F which closes a contact CMR-F and, consequently, the circuit between the battery and the forward drive terminal AV of the motor 40.

To rotate the electric motor 40 in the reverse direction, the manual transmission 22 is brought into the reverse position. This has the effect of closing the IPR switch for switching on the reversing lights and, consequently, energizing the R-6 relay which opens the contact.
CR-6 and closes the CR-6 'contact. Current cannot then pass through diodes Dl and D-2, but it can pass through diodes D-3 and D-4. The current flowing through the diode D-3 charges a CAV capacitor jerk forwards. The current passing through the diode D-4 excites the relay D-7 which closes the normally open contact CR-7. An MR-R relay is therefore energized, which causes the contact to close
CMR-R as well as that of the circuit leading to the reverse reverse terminal AR of the electric motor 40. The latter is then started in the reverse direction.

 The auxiliary motor circuit shown in Figure 4 has several safety features.

For example, the IAL ignition switch must be germinated before the device can be implemented.

In addition, as described above, the driver must press the accelerator pedal to close the IAC accelerator switch and he must partially engage the clutch to open the IE clutch switch. If one of these switches changes position during the operation of the auxiliary motor 40, the current supply to the latter ceases immediately. It therefore appears that the driver of the vehicle must occupy his seat and that he must carry out certain operations on the vehicle before the device can be implemented. These safety features eliminate the problems posed by an accidental starting of the auxiliary device, which can lead to an accident if the vehicle has limited space, for example in a garage or on a busy road.

 Other safety elements are also incorporated in the auxiliary motor circuit. For example, the ISM centrifugal motor over-speed switch opens the circuit and, consequently, cuts the current supply to the motor 40 when the latter reaches a predetermined speed. The engine overheating above a predetermined temperature also causes the excessive temperature ITE switch to open, which de-energizes the R-9 relay, the CR-9 'contact of which closes, thus causing the lighting of the VTE excessive temperature warning light, the CR-9 contact opening and thus interrupting the flow of current to the motor 40.

As previously indicated, when the electric motor is started in the forward direction or in the reverse direction, one or the other of the CAR capacitors and
Backward jerk and forward jerk CAV, respectively, charge. The current then stops passing through the relay R-3 when the circuit of the electric motor 40 opens, for example under the action of the over-speed switch, the excessive temperature switch or the switch. stop. The CR-3 contact then returns to its normal open position, while the CR-3 'contact returns to its normal closed position. The capacitor charged CCA for switching and jerky discharges into relay R-4 which momentarily closes the normally open contacts CR-o. The capacitor charged CAR or CAV then discharges into relay
R-7 or R-8, respectively. The current pulse passing through one or other of these relays R-7 and R-8 momentarily closes the contact CR-7 or CR-82 respectively. This allows a current pulse to momentarily actuate the electric motor 40 in the backward direction or in the upward direction, respectively, and, consequently, to disengage the coupling assembly, and wheel and wheel as previously written.

Under real operating conditions,
If the front wheel of the vehicle 10 according to the invention stops on ice, for example, the auxiliary device can be used. To start the device, the driver leaves the ignition switch in the closed position; he lightly presses the accelerator pedal; then it begins to release the clutch. I1 then presses the switch IN for starting the auxiliary device, this starting being indicated by the LED VM, which completely closes the circuit of the auxiliary motor 40. The rotation of the latter is then carried out in the desired direction, the motor 40 driving the rear axle as described above.

 When the vehicle has cleared the obstacle from the road, the auxiliary engine 40 can be stopped by means of the switch IA which opens the circuit of this auxiliary engine, as shown in FIG. 4. If the driver does not do not manually stop the device, the engine overspeed switch automatically opens the circuit when the auxiliary engine reaches a predetermined speed. The IF brake switch also stops the device when the driver presses lightly on the brake pedal.

It should also be noted that the auxiliary device according to the invention can be modified so that the auxiliary motor 40 is started automatically when the driving wheels spin. Such an automatic auxiliary control device requires an element intended to detect the slip of the front drive wheels. Such an element can be a speed detector such as a magnetic sensor 70 (shown in phantom in Figure 1) which 2tlLH teeth, ribs or other roughness 71, spaced regularly and circumferentially on the surface of the wheel drive 27 or on a ring fixed to this wheel. The detector output signal is transmitted to a logic element 72 of the device which compares the variations in speed of the wheel with an authorized range of variations in speed responding to a predetermined program. For any deviation from the authorized range, the logic element 72 actuates a switch 73 which connects the cables 62 to each other in order to close the circuit between the battery 18 and the auxiliary motor 40. The element logic 72 is also designed to open the switch 73 when the wheel stops spinning. Such wheel speed detectors are currently used with anti-slip brake systems which can be mounted on passenger cars and trucks. These braking systems can be easily adapted to automatically control the auxiliary motor device according to the invention.

 It should be noted that other types of auxiliary motors, for example hydraulic pump and motor groups, can be used in the vehicle according to the invention. These groups are well known to those skilled in the art and they are often used in devices cooperating with the power transmission of a vehicle. Hydraulic auxiliary motor elements generally draw their energy from the main motor and can therefore only be used in applications where the main motor supplies sufficient energy. However, the operating direction of the hydraulic pump and motor groups can be reversed by simply moving a hydraulic valve.

 It goes without saying that many modifications can be made to the vehicle described and shown without departing from the scope of the invention.

Claims (8)

1. Vehicle, characterized in that it comprises a first wheel and a first axle intended to control the first wheel, an internal combustion engine designed to drive the first axle, a storage battery intended to be charged by the engine internal combustion, a second wheel, a second axle and a device for selectively engaging the second axle with the second wheel, an electric motor which is engaged with the second axle and which can selectively engage with the second wheel by the intermediate of said second axle, this electric motor being connected to said battery, and a device making it possible to selectively start and stop the electric motor.  2. Vehicle according to claim 1, characterized in that it also includes a device for automatically disengaging said device selectively engaging the second axle with the second wheel when the electric motor stops  3. Vehicle according to claim 1, characterized in that the electric motor can operate in forward and reverse. 4. Vehicle according to claim 3, characterized in that it also comprises a transmission mounted between the engine and the first wheel and capable of operating in reverse, a reversing light control switch being actuated when said transmission operates in reverse. , an element causing the electric motor to operate in reverse when the reversing light control switch is actuated.  5. Vehicle according to claim 1, characterized in that it comprises an element intended to automatically stop the electric motor when the latter reaches a predetermined speed.  6. Vehicle according to claim 1, characterized in that it comprises a carburetor which regulates the speed of the internal combustion engine, the electric motor can not be started when the carburetor is in its idle position.  7. Vehicle according to claim 1, characterized in that it comprises an ignition switch which can be actuated for starting the internal combustion engine, the electric motor cannot be started when this ignition switch does is not operated.  8. Vehicle according to claim 1, characterized in that it comprises a brake which can be actuated to slow down the vehicle, the electric motor being unable to be started when the brake is actuated.