FR2680829A1 - DRIVING DEVICE FOR AT LEAST ONE AUXILIARY MOTOR ORGAN. - Google Patents

Abstract

The invention relates to the drive of auxiliaries of internal combustion engines. This device is constituted by an epicyclic mechanism in which a crown component (4) can take its reaction on the housing (7) with a variable torque. In order to be able to vary the transmission ratio of the device within the limits of a maximum bandwidth with simple means, it is proposed to realize the device for varying the reaction torque in the form of a pump (9, 4) delivering a liquid, the delivery rate of which is adjustable. Main application: motor fans.

Description

Drive device for at least one auxiliary engine member

  The invention relates to a driving device for at least one engine auxiliary member, comprising an epicyclic mechanism which comprises an input unit, an output unit and another unit which is supported by reaction on the housing. and a device for modifying, as a function of the operating parameters, the torque with which said other unit takes its reaction on the housing. It is known from a more recent patent application P 4,041,158 3-13 a drive device of the kind in question for the fan of an internal combustion engine. Here, it is intended to provide a reaction support. to the inner central wheel or planetary wheel of the epicyclic mechanism on the crankcase of the internal combustion engine by means of a hydrodynamic brake, and the reaction torque can be varied and, with it, the the speed of rotation of the fan, for a given number of revolutions of the internal combustion engine,

  Filling the hydrodynamic brake Since in a hydrodynamic brake the rotor can never be fully braked to a standstill, even at maximum filling, it is not possible to use the belt width. theoretically possible transmission ratio between input and output. It is known moreover from DE-A-3 821 367 to vary the transmission ratio of a speed multiplier by means of a hydraulic motor coupled to the planetary wheel of the epicycloidal mechanism and which is driven by a pump driven itself by the internal combustion engine However, this is a relatively expensive solution

  is. It is an object of the invention to provide a training device of the kind described at the beginning, in which the transmission ratio can be varied within the limits of a maximum bandwidth by means of simple. According to the invention, this problem is solved by the fact that the device used to vary the reaction torque is a liquid delivery pump which can be driven by said other unit and whose discharge rate is adjustable. The use of a liquid discharge pump with an adjustable discharge rate has the advantage of allowing, by reducing the discharge rate of the pump to zero, to brake up to The unit of the epicycloidal mechanism which takes its reaction on a stationary casing with the interposition of this pump is stopped. With this solution, it is therefore possible to vary the transmission ratio of the drive device in the transmission.

  The use of a single pump is also a relatively economical solution and, in the case where the pump is an internal gear pump integrated in the housing of the epicyclic mechanism, we can still save extra on the volume of space. Since with a suitable valve in the discharge line connected to the pressure side of the pump, the discharge rate or the pressure in that line can be varied relatively quickly and, in this way, the speed of rotation of the pump, it is also possible to obtain, if necessary, a very fast variation of the transmission ratio. By using a pressure limiter upstream of a valve that controls the discharge flow as a function of

  In some engine operating parameters, it can be ensured that the auxiliary member can already be driven with high power at low input speeds, but that any deterioration of the auxiliary member can, however, be excluded in all cases. In this case, even at high input speeds, it is possible to limit in a simple manner the power of the auxiliary element considered, which may be for example a fan. According to another characteristic, the suction chambers of the pump are connected, by openings formed in the sealed separating plate, to a lubricating oil reserve compartment provided in the epicyco Idal mechanism casing, and which is in communication with the lubricating oil circuit of the engine. This feature has the advantage of eliminating the need to provide a separate liquid circuit for the operation of the pump according to the invention.

  On the other hand, with this characteristic, the heat released as lost energy is removed in a simple way. The invention is described below with reference to the drawing which shows an exemplary embodiment. In this drawing, Figure 1 shows a device according to the invention for driving the fan of an internal combustion engine, a schematic cross sectional diagram; Figure 2 is a sectional representation of the object of Figure 1, taken along the line II-II; and Fig. 3 is a graph PL = f (n) illustrating the relationship between the fan power PL and the rotation speed N of the internal combustion engine. Figure 1 represents a multiplying mechanism

  The multiplier mechanism 1 is an epicycoldal mechanism which is composed of an inner central wheel or planetary wheel 3, a planet carrier 1 for the fan 2 of an internal combustion engine not shown in the drawing. 5 on which are rotatably mounted the planet wheels 6, and an outer center wheel, or crown 4 The sun gear 3 is rigidly coupled in rotation to the fan 2 and the input is via the planet carrier 5 which is integrally connected in rotation to the crankshaft, not shown in the drawing, of the internal combustion engine The casing 7 which encloses the various components of the multiplier mechanism 1 takes its reaction on the casing 8 of the internal combustion engine (This is represented in the drawing only by symbols). The ring gear 4 is relatively wide, so that, in addition to the planet wheels 6, the internal gear 9 of an internal gear pump 10, also contained in the casing 7, serves to discharge a liquid.

  The ring gear 4 thus additionally forms the outer toothed wheel of the inner gear pump 10. The watertight separation of the inner gear 9 is ensured by the ring gear 4. 1 side by the casing 7 of the epicycloidal mechanism and, on the other side, by a separating plate 11, rigidly secured to the casing 7 and which is interposed between the internal gear 9 and the rolling plane of the satellite wheels 6, and engaged in a circular inner groove 9 formed in the crown 4 The inner gear 9 journalled, on one side, in the partition plate 11 and, on the other side, directly in the housing 7 On the 2, it can be seen that the casing 7 of the epicyclic mechanism surrounds the internal gear 9 so that this inner gear 9 isolates from each other

  two chambers 13 and 14 If the ring gear 4 rotates in the direction of the arrow 15, it causes a rotation of the inner gear 9 in the direction of the arrow 16, which has the effect that the liquid to be discharged (here the engine oil) is sucked into the chamber 13 by the toothing of the inner gear 9 and, likewise, into the chamber 13 'by the toothing of the outer ring 5 - and pushed back into the chamber 14 Since after having traveled the chamber 14, the toothing of the planetary wheel 9 is again engaged with the crown toothing 4, the engine oil which is in the teeth of the toothed wheels 4 and 9 is expelled, so that The chamber 14 thus forms an overpressure in the chamber 14 and thus the chambers 13 and 13 'form the suction chambers of the internal gear pump 10. The suction chambers 13 and 13 'are connected to the chamber 18 (FIG. 1) of the epicyclic mechanism, each by a through hole 17 and 17 '(FIG.

  This chamber 18 is in turn in communication with the lubricating oil circuit of the internal combustion engine. It is ensured at all times that the filling height of the tank 7 of the The epicyclic mechanism can never fall below the level indicated by the broken line 19 This precludes the risk of the pump 10 sucking air through the through bores 17 and 17 'At the same time, always gets optimum lubrication of the different components of the epicyclic mechanism. According to another embodiment of the invention, it is also possible to give the closure plate an extended configuration over the entire inside diameter of the crown, so that the space in which the satellites circulate is insulated with a tight seal to the liquid of the chamber in which the internal gear pump works. In this case, it is possible to use for the operation of the internal gear pump a liquid different from that used for lubrication. Of course, in this case the crown must be constructed so that it can be divided. At the pressure chamber 14 there is provided in the housing 7 of the epicyclic mechanism a bore 20 to which is connected a discharge line 21 whose flow section can be adjusted continuously by means of a valve 22, between a position which reduces the section to zero (closing position) and a section which clears the entire section of the pipe 21 (maximum open position). The valve 22 is controlled by an electronic control unit 23 as a function of motor operating parameters which are transmitted to the control unit 23 via lines 24 of measured values. These parameters are, for example, the load of the internal combustion engine. - dull, its speed of rotation, the temperature of the coolant of this engine, the temperature of an additional braking device coupled to the engine with com-

  internal combustion, for example a retarder, the temperature of the supply air, the temperature of the oil, etc. The discharge line 21 opens, downstream of the valve 22, into the oil reserve casing internal combustion engine (arrow 25) or, in the case where the oil return to the lubricating oil sump of the internal combustion engine is effected by a separate valve, this line is returned The output rotation speed of the epicycloidal mechanism and, with it, the speed of rotation of the fan, vary for the same input speed depending on the torque with which the ring gear 4 is braked or In turn, the torque depends directly on the dynamic pressure prevailing in the discharge pipe 21, and therefore on the open position of the valve 22. If this valve is in its position of maximum opening, the pump 10 can thus return to the maximum flow rate. In this case, the dynamic displacement in the discharge pipe 21 is minimal, ie the speed of rotation of the internal gear 9 is maximum and the braking torque acting on the ring 4 is therefore minimal. . If, on the contrary, the valve 22 is in its closed position, the pump 10 can no longer pump motor oil, that is to say that the internal gear 9 can no longer rotate. is therefore immobilized since, now, it is indirectly takes its reaction on the casing 7 via the incompressible motor oil which is on the pressure side (via the bearings of the inner gear 9 ). There is a proportional relationship between the

  In this way, by varying the opening position of the valve 22, the reaction torque of the ring 4 can be varied by continuously varying the pressure in the discharge line 21 and the speed of rotation of the ring 4. and, as a result, the output speed (rotational speed of planet wheel 3). If the internal combustion engine is working at a determined rotational speed n, the satellite carrier 5 obviously rotates with the same rotational speed. The circumferential speed measured at the external circumference of the planet carrier 5 (radius rm ) then corresponds to the length of the arrows 26 and 27 in diagrams A and B of FIG. 1. In these diagrams A and B, the circumferential speeds v of the different rotating elements of the epicyclic mechanism are plotted as a function of the radius r. of the corresponding wheel (ra = radius of the crown 4, rm = radius of the planet carrier 5 and ri = radius of the sun wheel 3). Diagram A shows the conditions prevailing when the valve 22 is open to the maximum. In this case, a maximum oil flow can be repressed, that is to say that the speed of the The rotation of the inner gearwheel is maximum and, consequently, the torque with which the ring gear 4 is braked is minimal. The ring gear 4 therefore rotates at a relatively high rotational speed. The circumferential speed is represented in this case on the diagram. A by the arrow 28 If we join the tips of the two arrows 28 and 26, we obtain, as indicated by the arrow 29, on the radius ri of the sun wheel 3, a circumferential speed v that is relatively low ( The length of the arrows is a measure of the value of the circumferential velocity v at the radius considered ra, rm and ri) The output rotation speed of the epicycloidal mechanism and, with

  the speed of rotation of the fan is therefore relatively low in this case. If the discharge line 21 is closed by the valve 22, the internal gear 9 of the gear pump 10 and with it also the ring 4 are braked to a standstill, i.e. the circumferential velocity v measured at the radius ra vanishes. By connecting the zero point 30 of the radius ra to the tip of the arrow 27 in the diagram B, a circumferential speed v is obtained which is now higher at the radius ri of the sun wheel 3 and, therefore, a higher rotational speed of the fan (arrow 36). With respect to a given input speed or circumferential speed given to the radius rm of the planet carrier 5, the output rotation speed or the circumferential speed at the radius r 1 of the planet wheel 3 is maximum when the speed circumferential - the v measured at the radius ra of the ring 4 is zero, that is to say when the ring 4 is immobile. The higher the rotational speed of the ring gear 4, the lower the output rotation speed of the epicycloidal mechanism and, with it, the rotational speed of the fan. Of course, it is never possible to completely avoid any loss of leakage on the pressure side of the gear pump 10, ie the inner gear can still turn slightly even when the valve 22 is closed, but the influence of this rotation on the output rotational speed of the epicyclic mechanism is reduced to an insignificant value. According to another characteristic of the invention, it is also possible to provide upstream of the valve 22 a pressure limiter 31 (shown in broken line).

  pu), with which it is possible to prevent the dynamic pressure in the discharge line 21 upstream of the valve 22 from becoming greater than a limiting value and that the speed of rotation of the fan then takes value too high in terms of solidity The pressure limiter 31 functions in such a way that, when the predetermined limit value of the dynamic pressure is reached, a partial flow of the engine oil It is deviated by means of the limiter 31 and, more precisely, exactly the flow rate that is necessary so that the pressure in the pipe 21 does not become greater than the limit pressure. A limitation of the power is thus achieved. FIG. 3 shows, by a graph PL = f (n), the relation linking the power PL of the fan to the rotation speed N of the internal combustion engine

  in the case where the valve 22 is open to the maximum (curve 33 in solid line), and in the case where the discharge pipe 21 is completely closed by the valve 22 (curve 34 in broken line) When the pipe 21 is closed, the rotation speed of the fan and, with it, the power PL of the fan are always greater than they are when the discharge pipe 21 is cleared The curve 34 is therefore above the curve 33 to all the rotation speeds N of the internal combustion engine With the pressure limiter it can be achieved that, when the duct 21 is closed, the fan power curve becomes almost horizontal from a predetermined threshold ns of the speed of rotation of the motor This is indicated by the line in phantom in the diagram of FIG. 3 With this solution, it is possible to make the fan 2 work if necessary entirely in circuit on all i different speeds of rotation (that is, when the

  discharge pipe 21 is closed by the valve 22) so that almost the maximum power P Lmax of the fan is obtained at a relatively low speed of rotation of the internal combustion engine. However, it is excluded at any time that the fan may be damaged due to a too high rotational speed in the upper range of the rotational speeds of the internal combustion engine. However, with this solution (controllable valve 22 and pressure limiter 31 interposed upstream) it is possible to work where necessary at any desired point between the three curves 33, 34 and 35. The pressure limiter 31 does not have to be interposed in series with the controlled valve 22, it can also be bridged. - in parallel with this one. The use of a pressure limiter 31 a

  Moreover, the advantage is that the entire system can react particularly rapidly to an exceeding of the speed limit of the dynamic pressure in the discharge line 21. The broken curve can also be obtained without using a speed limiter. pressure 31 but, in this case, must be provided in the discharge line 21, upstream of the valve 22, a separate sensor by means of which the actual dynamic pressure can be transmitted to the electronic control device 23 which, when the pressure limit is reached at the threshold ns of the rotational speed of the internal combustion engine, controls the valve 22 in such a way that by releasing the flow section of the discharge pipe 21 accordingly, the line curve 35 is produced. mixed Control can also be performed using a sensor that detects the speed of rotation of the fan. According to another characteristic of the invention, provision can also be made for driving 21

  only a pressure limiter, which, when the limit pressure is reached, deviates a corresponding oil flow In this case, the curve 34 would be followed in a broken line going from the idling speed n LL up to the limit speed ns, while at the higher rotational speeds, the dashed line curve would be followed. Instead of a gear pump, it is also possible to use a semi-rotary cell pump with propulsion or blocking valves as a liquid discharge pump. If the pump is constituted by a pump with solenoid valves blocking, the discharge elements can be arranged on the back of the ring gear and the blocking valves in the casing A propulsion valve pump would require a machined casing with an eccentric shape, as well as a valve in the ring gear.

  Naturally, the variable torque reaction must not necessarily take place on the epicyclic mechanism crown. According to the invention, this reaction can also be carried out on another element. the output must then be studied accordingly.

Claims (7)

CLAIMS 1 Training device for at least one organ   engine auxiliary, comprising an epicycloidal mechanism which comprises an input unit, an output unit and another unit which bears on the housing, and a device for modifying, as a function of the operating parameters, the torque with which said other unit takes its reaction on the casing, characterized in that the device used to vary the reaction torque is a liquid discharge pump which can be driven by said other unit, and whose discharge rate is adjustable.   2 Drive according to claim 1, characterized in that the input unit is the planet carrier (5), the output unit the planet wheel (3) and the said other unit the ring gear (4). ) of the epicycloldal mechanism.   3 Drive according to claim 2, characterized in that the liquid delivery pump is an internally geared pump (10) whose external gear is constituted by the internal toothing of the ring gear ( 4) of the epicyclic mechanism.   4 Drive device according to claim 3, characterized in that the width of the inner toothing of the crown (4) is greater than the width of the toothing of the planet wheels (6) and in that the inner toothed wheel (9) of the pump (10) is engaged with the inner tooth of the ring gear (4), the seal-tight insulation of the inner gear wheel (9) of the pump (10). ) being provided by the housing (7) and by a sealing plate (11) arranged between the rolling surface of the planet wheels (6) and the inner gear wheel (9) of the pump (10), rigidly connected to the carter (7), and engaged in a circumferential inner groove (12) made in the crown (4).   5 Drive according to one of claims 1 to 4, characterized in that the pressure chamber (14) of the pump (10) is connected to a pipe (21) for discharging the liquid whose flow section can be adjusted using a valve (22).   6 Drive device according to claim 5, characterized in that upstream of the valve (22) is arranged a limiter (31) which limits the pressure in the discharge line (21). upstream of the valve (22).   7 Drive device according to claim 1, characterized in that the suction chambers (13, 13 ') of the pump (10) are connected via openings (17, 17'). ) provided in the separating plate (11) to a lubricating oil reserve compartment (18) provided in the epicycoldal mechanism housing (7), which is in communication with the engine lubricating oil circuit.