BE544292A - - Google Patents

Description

       

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   The present invention relates to engine blocks and relates, in particular, to engine blocks comprising hydraulic torque converters of the hydrodynamic type. More particularly still, the invention relates to engine blocks, in which these converters are combined with engines driving combustion engines.



   The invention is particularly applicable to the propulsion of vehicles or other forms of traction controls and, although it is not limited to this field of use, the invention will be discussed and its advantages will be highlighted. in its application to the controls of motor vehicles, because of its particular application faculty to this type of control.



   In vehicle controls employing variable speed power transmission devices, it is ordinarily desirable to provide a relatively high rate of torque multiplication under a stalled or stalled condition of the driven element, in view of the to produce rapid acceleration and also in order to dispense with a high pulling force at low vehicle speeds.

     In hydraulic torque converters of the hydrodynamic type, as designed heretofore, the desired high rate of starting or stall torque has been obtained from either of the two. two following manners, namely by providing in the hydraulic circuit, at least one three-stage turbine, by which torque multiplications of the order of 5 to 6 or more to 1 are obtained during a stall ,

   or by combining a torque converter fitted with a turbine comprising

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 only one or two stages with some form of auxiliary torque multiplication gear to further increase the starting torque ratio when needed or under other conditions requiring higher torque multiplication than that which is capable of providing a torque converter with one or two stages, unless the converter is connected to the wheels of the vehicle in such a way as to materially reduce the maximum speed of the vehicle which can be effectively obtained under hydraulic control, in comparison with practices usual.

   These two expedients are relatively expensive, either because of the cost due to having to provide multistage converters with a relatively large number of rings or fin rings, or because of the cost due to having to provide an auxiliary gear *
On the other hand, torque converters, as heretofore constructed, usually exhibit a relatively constant torque absorption characteristic, which allows the engine to accelerate rapidly to maximum speed or to maximum speed. at a speed close to the maximum speed, when the throttle is placed in blocking conditions.

   This gives rise to a relatively very rapid application of full engine power during stalling and at very low turbine shaft speeds without resulting in a corresponding increase in torque. secondary. This type of operation is also undesirable in many other cases, because of the noise level resulting from the rapid acceleration of an engine from idling to full speed or to a speed substantially such at the time. blocking and throughout the acceleration period, while it is also

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 This is undesirable because of the resulting poor fuel economy.



   Modern high-speed combustion engines have operating characteristics, which are very different from those of older, low-speed engines. There are engines which, both in terms of speed and performance characteristics. torque are extremely smooth over a relatively wide range of speeds. Typical examples of such engines are those which produce maximum torque at speeds close to half the speed at which full power is developed, with the torque increasing from idle speed to maximum somewhere around half full speed and then decreasing noticeably as speed increases to where full power is reached.

   In some cases, the torque loss can be up to 40% or more than half of full speed at full speed.



   In view of the aforementioned characteristics of certain types of engines, as well as the torque conversion characteristics of the turbine type of a hydro-dynamic converter, the general object of the present invention is a new and improved form of hydraulic circuit, which in turn. Particularly in combination with an engine having variable power and torque characteristics of the general type mentioned above, will allow an overall improved performance of tractive forces over a wide range of speeds including the required high torque of the engine. driven shaft in case of jamming and with high peak efficiency,

   with a lower number of fin stages than that required hitherto in a comparable installation and with

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 torque absorption characteristics to take maximum advantage and advantage of the output torque characteristics and flexibility of the motor.



  A further object of the invention is a new form of hydraulic torque converter which, while exhibiting the characteristics noted above, is capable of operating in two different ways in two different ranges of speed of the motor. 'driven or output element, so that in the low speed range a torque multiplication equal to or greater than that obtained with a greater number of stages is ensured without increasing the number of rows of fins required,

   while in the high speed range of the driven element a higher efficiency is maintained and a multiplication or increase of torque is obtained up to a relatively high ratio of the speed of the element. driven to that of the drive element. Another subject of the invention is a novel torque converter arrangement having the advantages mentioned above and allowing, moreover, the use of the hydraulic torque converter mechanism alternately with a direct mechanical control.



   Other objects of the invention, as well as the advantages resulting from its implementation will emerge from the following description, in which are described, by way of nonlimiting examples, some suitable embodiments of the invention. an apparatus for implementing the invention, with reference to the accompanying drawings, in which: - Figure 1 is a central longitudinal section of the part of the hydraulic circuit of a converter constituting an application of the principles of invention; - Figure la is a section along line la-

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 1a of FIG. 1 and also comprising a speed diagram showing the value of the flow of the fluid leaving the last fins of the turbine at the time of blocking;

   - Figure lb is a section along the line Ib-1 ± of Figure 1 and including a speed diagram showing the flow of fluid at the inlet of the pump, at the time of blocking; - Figure 1c is a diagram similar to that of Figure 1, but showing the flow conditions at the point of reversal or change of direction; FIG. 1d is a speed diagram similar to that of FIG. 1b and showing the conditions of flow of the fluid at the inlet of the pump at the point of overturn or change of direction; FIG. 1e is a diagram illustrating the input torque absorption characteristics of a converter implementing the principles of the present invention;

   FIG. 1f is a diagram showing the power and torque characteristics of an engine / type according to the present invention; - Figure 1g is a diagram similar to that of Figure le; Figure 2 is a section similar to that of Figure 1 showing another form of converter applying the principles of the invention; FIG. 3 is a more or less conventional diagram illustrating certain characteristics of torque of converters according to the invention; - Figure 4 is a longitudinal central section

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   of a converter according to the invention comprising a direct mechanical control to be used alternately with a
 EMI6.1
 6on control: vrtisseur; - Figure 5 is a section along the line V-V of Figure 4;

   FIG. 6 is a section similar to that of FIG. 4, showing another similar form of converter with direct control according to the invention; - Figure 7 is a section taken along the line VII-VII of Figure 6, and - Figure 8 is a diagram illustrating the performance and torque characteristics of converters of the type shown in Figures 4 and 6.



   The mechanism illustrated more particularly in FIG. 1 comprises a fixed casing 16, in which is mounted, so as to be able to turn, a pumping wheel constituting the drive element of the apparatus and comprising a disc 24 carrying a crown of vanes or vanes 28 and a
 EMI6.2
 hub or hollow shaft part 24a'-intended to be connected to the crankshaft or other driven element of a motive machine. In the torus-shaped chamber -formed by the casing 16 is also mounted, so as to be able to rotate, the turbine element or driven element comprising a disc 42 and a hub or hollow shaft part 44.

   The disc 42 carries two rows of turbine fins 34 and 36, the first being disposed radially outside the vanes or fins 28 of the pump in the radial outlet part of the circuit, while the turbine fins of the second row are mounted in the radial inlet part of the circuit.



   A ring of fins 46 mounted in the circuit between the fins 34 and 36 is carried by a disc 50 connected

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 to the hollow hub or part of a shaft 48 or integral with the latter. For ease of description, the fins 40 will be referred to as reaction fins, although, as will be apparent from the following description, these fins may in some of the structures according to the invention. constitute rotating fins rather than fixed reaction fins, in which case they also share the nature of turbine fins, since they transmit energy to the driven elements when they rotate in an opposite direction to that of the pump fins
Advantageously, the turbine and reaction fins have

   but not necessarily the general shape of profiles with a rounded inlet portion, as in the case of the fins described in U.S. Patent Lysholm No. 1,900,118. Moreover, as will be seen in FIGS. 1a and 1b, the angular positions of these fins are such that, when the hydraulic fluid is circulated by the pump in the direction indicated by arrow 56, it will tend to rotate the vanes 34 and 36 in the same direction as the direction of rotation of the pump and will tend to rotate the reaction vanes 46 in the opposite direction of rotation
The general arrangement of the apparatus shown is known and suitable for use in conjunction with a direct mechanical drive as illustrated in U.S.A.

   Lysholm 1.900.119, a direct drive shaft 8, which passes through the hollow shaft parts 24a and 44, which can be directly connected either to the output element of the prime mover or to the engine. pump element 24a by means of suitable couplings, while the turbine element or driven element 44 can be connected to the direct drive shaft 8 via a coupling

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 training. Since these structural arrangements are well known in the art (see US Pat. No. 1,900,119) it is not necessary to illustrate and describe them herein, in order to understand the present invention. .

   The reaction vanes 46 can be blocked against rotation by connecting the shaft 48 to the stationary housing 16 or, as will be explained in detail later, the shaft member 48 can be connected to the. using a gear suitable for the driven shaft member 44, so that the vanes 46, instead of remaining fixed, rotate in the opposite direction to the direction of rotation of the vanes 34 and 36.



   An important difference between prior arrangements and the present invention is in the positions of the turbine and reaction fins relative to the pump and, in particular, in the relative radial positions of the last stage of the turbine and the pump. As can be seen from FIG. 1, the fins are arranged so that the last stage of turbine fins 36, which rotate in the same direction as the pump, leads directly to the inlet of the pump, without interposing between these fins any uide or reaction fins or turbine fins rotating in the opposite direction.

     It will also be observed that by placing the reaction fins and the input last stage of the turbine fins * on the / radial side of the circuit opposite to the side in which the pump is placed, and by placing, moreover, the first stage of turbine fins 34 immediately outside the discharge side or edge of the pump fins, there is sufficient room for the outer edges h of the turbine fins 36, which terminate in pump, can be located at a radial distance from the axis of rotation.

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 very large, without having to use very low profile dimensions.



   The importance of the general arrangement described above and of the relationship described above between the fins is that with such an arrangement the characteristics of the converter are made such that when the speed of the turbine element or driven element decreases with respect to the speed of the. pump in the direction of a stall or towards a stop, the absorption capacity of the converter cup increases relatively sharply, so that the load applied to the motor and consequently its speed increases. , even if it operates with full throttle, are appreciably reduced as the turbine approaches the stall state.

   This provides a highly desirable market characteristic for the prime mover as a whole. as will be explained more fully in the remainder of this memorandum.



   The pattern of the increase in the torque absorption characteristic, obtained with a fin arrangement as described above, can best be understood by considering the following discussion of the factors involved)! taken into account, this discussion being made with reference to the diagrams of Figures la to 1d.



   The pressure in the hydraulic water column produced by a propeller of the bladed or fin type, such as the pump employed in converters of the type in question, which constitutes a measure of the input torque required to run the pump, is expressed by the following well-established formula:
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 in which :
H is the pressure developed by the pump; p is the efficiency of the pump; g is gravity; ub is the peripheral speed of the pump at the outlet; u is the peripheral speed of the pump at the inlet;
C is the absolute speed of the working fluid;
Ctb is the projection of C on the tangent of the circle of the pump at the outlet;
C ta is the projection of C on the tangent of the circle of the pump at the inlet.



   It is immediately seen, by considering the formula given above, that the value of Hp changes when the value of the factor Cta changes, assuming that nI and Q are inta changed and, in accordance with the present invention, Hp decreases abnormally, when increasing the ratio of the secondary speed or speed of the turbine n2 to the primary speed or speed of the pump n1 (n2 / n1). The change in the ua.Cta factor depends on the change in energy after the turbine supplies fluid to the pump.



   If, for example, a torque converter is available, the pump of which has a certain inlet diameter, the following results will be obtained. We will first consider the speed diagrams forming part of Figures 1a and 1b, which illustrate the flow conditions obtained at the outlet edge h of the last stage of turbine blades and the inlet flow conditions prevail at inlet edge has fins of the pump, when the pump is in narche and the turbine is stationary or stopped, that is to say when the ratio n2 / n1 is equal to infinity.



  In the diagram of figure la, the vector C indicates the

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 , absolute speed and the direction of the fluid leaving the fins 30, this vector also indicating, since these fins are fixed, the relative speed wh, given that the peripheral speed of the fins u, is equal to zero. The projection of C on the tangent of the outlet circle of the turbine, extends, retort shown in the diagram, in the opposite direction with respect to the normal direction of rotation of the fins and presents a negative value to the stop.

   If this negative value were to be substituted into the equation given above (in other words, if one were to assume that Cth was equal to Cta), the expression in which this factor occurs would be negative and, given if the expression as a whole is negative in the equation, the factor in question would be positive in it, so that Hp would have a higher value than if Cth were positive.



   However, it is fundamental for hydraulic circuits of the type in question that the tangential flow component liter C t increases when the line decreases *. of the circle to which the current is tagent and this increase is directly proportional to the change in the radius of the circle. In this regard, it should be noted that this change in tangential is independent of the variation of the speed / speed of circulation of the fluid in the circuit, that is to say of the quantity of fluid circulated by the vane. - te per unit of time.

   The effect of this characteristic is best illustrated by the diagram associated with Figure 1b, which illustrates the flow conditions prevailing at the inlet of the pump with the arrangement shown, when the turbine is at the pump. stop. In this diagram, the vector u here indicates the peripheral speed of the vanes of the pump, while the vector Cta represents the tangential speed component of the fluid arriving at the vanes. By comparing the diagrams of figures la and 1b, we will see that the vector Cta is

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 significantly larger than the vector Cth.

   When the fins are arranged as shown in Figure 1, the radius of the edges h is approximately 30% greater than the radius of the edges a and, therefore, the vector Cta is approximately 30% greater than the vector C. The direction th of the vector Cta is still negative and, by substitution in the aforementioned inequation, we would obtain a significantly higher value of H p than if the vector Cth were substituted in this equation, which would be the case if the radii of the edges a and h were equal.

   Consequently, by placing the outlet edges of the last stage of the turbine, which rotates in the same direction as the pump and directly feeds the latter at a substantially greater radial distance from the axis of rotation than the edges input from the pump vanes, significantly higher torque absorption characteristics are imparted to the pump at standstill than would otherwise be the case.



   Although the condition discussed above and prevailing at standstill is highly desirable for the purposes of the present invention and may vary in degree to suit particular conditions, by choosing the appropriate relationship between the radial distances to which - the edges a and h are located, this condition would not be desirable if a more or less constant relationship had to be maintained in the normal range of operating speeds of the turbine. However, this constancy of relation is not obvious, as can be explained with reference to figures le and Id.

   These figures show, in the form of diagrams, the conditions that can be obtained in a typical model, when the ratio of wines n2 / n1 is greater than 0.5, which is representative of the highest part.

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 of the normal range of turbine speeds by means of
Sleeps at the speed of the pump, the converters of the drive in question usually reaching an operating state in which the output torque falls to a value equal to the input torque, when the speed ratio n2 / n1 is of the order of 0.0 to 0.8.



   In the diagram of figure lc, the peripheral speed of the blades of the turbine is represented by the vector uh. The relative speed of the fluid leaving the fins of the turbine is given by the vector wh and, as a function of the peripheral speed uh, the absolute speed of the fluid leaving the fins is given by the vector ch.



  The tangential projection of this speed is given by the vector Cth and it will be observed that the direction of this tangential component of speed is the same as the direction of rotation of the vanes, so that the direction or the sign of this factor is positive rather than being negative as at standstill.



   If this positive value is substituted in the formula given above, the factor in the equation of which it is a part is positive and is, therefore, subtracted rather than added to the remaining factors in the discharge. It follows that the hydraulic pressure produced by the pump is lower than when it was stopped.



   If we now consider the diagram in Figure 1d here, the peripheral speed at the inlet of the pump is shown by the vector u, the relative speed of entry of the fluid into the pump by the vector wa and the speed .absolute of the liquid at the inlet of the pump by the vector C. The tangential component of the absolute velocity is shown by the vector Cta and, as well as at standstill, by the difference between the radial distances at which are found

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 the edges It and! of the fins, the tangential component Cta is greater than the component Cth, the difference between the magnitudes of these. components being proportional to the ratio between the radii a and h.

   It follows that if we substitute the larger positive value of Cta in the formula, we obtain a further decrease in the value H.



   P
Referring again to the four diagrams of Figures la to Id, it can be seen that the displacement of the outer or exit edge of the last stage of the turbine blades, so that this edge is at a greater radial distance than the inlet edge of the pump vanes, has the effect of appreciably increasing the torque absorption characteristic of the pump, when the speed of the turbine decreases from its normal operating speed to l 'stop, in comparison with a structure in which two sets of fin edges are on the same radii or substantially on the same radii of in which the exit edges of the turbine fins are on a shorter radius than the inlet edges of the pump fins.

   Assuming, for example, that edges a and h are on the same radius, the difference in the value of H when stationary and a p-value of 0.5 or more, for the gear ratio n2 / n1, is represented by the change in the values of the vectors Gth and Cta, which in this case are equal, the value of Hp increasing, but only to a small extent, when the speed of the turbine decreases from a n2 / n1 ratio until the stop.



   On the other hand, with the present arrangement, this change in the value of H, as the speed of the turbine decreases towards stop, is represented by the change in value of the product of the vectors Cth ua and, co. :

  i ... e he ras-

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 Leaving from the previous discussion, this represents a very noticeable increase in the quantity by which the pressure in the rupture is increased when stationary, when the edges are placed, at the outlet of the last stage of the turbine appreciably further of the axis of rotation as the inlet edges of the pump fins
It is well known that the speed of circulation of the working fluid in the circuit is a function of the hydraulic pressure Hp developed by the pump, this speed increasing as the hydraulic pressure increases. Consequently, the present structure which tends to increase rapidly the value of Hp, when the turbine approaches the stop, also produces an increase in the circulation speed,

   so that the torque absorption characteristic of the converter increases rapidly as the turbine speed decreases. The desirability of this characteristic, especially when combined with certain torque output characteristics which can be obtained in internal combustion engines, will be shown later, but before considering this phase of the invention another -characteristic of the nature of the increase in torque absorption, when approaching the state stalling or stopping, must be taken into consideration, this further characteristic being obtained by the present invention.



   As noted above, a basic feature of converters of the kind in question is that the value of the output torque or secondary torque decreases as the speed of the turbine element increases to. from standstill until a value equal to the input torque, before the speed of the turbine element reaches the speed of the pump, the value of

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 n2 / n1 ratio at which the torque ratio becomes 1: 1 usually somewhere in the range 0.6 to 0.8.

   The ratio of, speeds n2 / n1, for equal, for water the torque ratio becomes 1: 1, is commonly referred to as the transition point, since when the torque ratio toabe at 1 : A form of control other than continuous torque converter control should be employed, if a higher ratio between the speed of the driven shaft and the speed of the motor or pump is desired. It is highly desirable, for reasons which will be discussed later, to provide for the purposes of the present invention that a relatively high ratio is obtained between the values of the blow absorption characteristic of the con- vertisseur at the transition point and the torque absorption value at standstill.

   In many cases, it may be desirable to provide a structure, in which the converter will absorb 5-6 times or more of torque at standstill than at the transition point and , in some cases it may be desirable for the torque absorption at standstill to reach up to 10 times the torque absorption at the point of transition.



   It has been seen previously how, in accordance with the present Design, the torque absorption at standstill - in comparison with the torque absorption at or near the transition point, can be significantly increased by the positions. relative radials of some of the edges of the fins. It has been found that there must be some necessary relation between the radius of the outlet edges of the blades of the last stage of the impeller and the radius of the inlet edges of the fins of the pump, if the desired results.

   The nature of this relationship

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 can best be understood by referring to figure le, in which the ratio of the input torque at standstill (m1 at standstill) with respect to the torque at the transition point (M1 transition) is plotted on the ordinate, while the The ratio of the radius (r,) of the outer edges of the fins of the last h stage of the turbine to the radius (ra) of the inlet edges of the fins of the pump is plotted on the abscissa.



   In the diagram, curve M represents the ratio of the input torques at standstill and at the transition point. As the nature of this curve shows, the increase in the value of the input torque ratio to. stopping at the input torque at the transition point is not made in a straight line as a function of the increase in the line of the outer edges of the blades of the turbine relative to the radius of the input edges. of the pump fins.

   On the contrary, the more the ratio mentioned last increases, the more quickly the ratio of torques increases and, as the curve in question reveals, by placing the fins of the last stage of the turbine so that their outer edges are within a radial distance included in an interval not exceeding by more than about 15% that of the inlet edges of the vanes of the pump, a small appreciable effect is produced in that an increase occurs. - ratio of input torques at stop and at the transition point.

   As shown by curve M, which is based on test results, a value of approximately 2.5 for the torque ratio at standstill and at the transition point for a given converter has been obtained with a fin arrangement, in which the outlet edges h of the turbine blades and the inlet edges of the pump fins were approximately slow at the same distance

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 angular.

   In such a converter, the offset of the edges h of the blades of the turbine up to a-? angular distance exceeding by about 10% the distance from the inlet edge to the vanes of the pump, resulted in only a very small increase in the value of the torque ratio at standstill and at the transition point , namely an increase to a value a little higher than three.

   On the other hand, however, a change in the position of the outlet edges h of the blades of the turbine to a position where the radius is 50% greater than that of the inlet edges has the fins. of the pump resulted in an increase in the value of the torque ratio at the inlet and at the transition point of about 18. In other words, an approximately sevenfold increase in the value was obtained. of the report.



  A value of 18 of this ratio is a value which is ordinarily not necessary. Other factors ordinarily make a suitable design of a converter with an rh / ra ratio of 50% or more more difficult than design of an equivalent converter with a lower value of this ratio. Accordingly, in order to obtain the maximum benefit from the present invention, it is preferable to arrange the fins so that the ratio rh / ra is between a lower limit of about 1.15 and an upper limit determined by practical requirements, but usually not greater than about 1.5.



   However, the inlet radius of the pump does not have a constant value, while the variation of the inlet radius of the pump has no influence on the slope of the torque curve, which as we have seen. a mentioned above depends on the variation of the energy, between the stop and the transition point, contained in the circulating fluid, when this one leaves the turbine in front of the pump

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As a fixed and unchangeable factor for the relative vis-à-vis the exit radius of the last row of turbine fins, the external diameter of the hydraulic circuit was chosen, which constitutes a measure, used internationally, of the dimensions of the system. .

   It was then noted that the values according to figure lg for Marrêt and M transi- point will vary between the limits given by the following expressions:
 EMI19.1
 where rh is the exit radius of the last turbine and rc is the outer radius of the working chamber, so that according to the invention rh / rc will vary from 0.5 to 0.8. A variation of 0.53 to 0.63 has been found to be very important for converters intended for passenger vehicles.



   We then start, for the calculation, from the same formula as previously, namely from
 EMI19.2
   However, u = rc. #, # Being the angular speed of the pump. The last factor therefore becomes ra. # Cta. # (ra. Cta). In the space between the last turbine and the pump, the relation ra. Cta rn. This is however prevalent. So the formula can be changed to
 EMI19.3
 
If we compare this formula to the previous one, we find that the factor u. C has been transformed into usr. C at ta h th in which we assume that the factor ur is constant
We thus obtained a term for Hp in which rh

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 only is included and not as previously in relation to the inlet radius of the pump.

   This is why it has been considered that it is more justified to refer rh to the outer radius rc of the hydraulic circuit.



   At the rh stop. Cth is negative, as it was shown previously, which will increase the value of Hp and consequently the Off. This increase will be greater as rh increases. At the rh transition point. Cth is positive, as also shown previously, and will decrease the value of Hp and thus the Mtransition 'so that the decrease will be all the greater as rh increases. It follows that Marrêt / Mtransition, increases, if rh increases .



    Celé. means that, for a constant input torque, the motor speed will be lower at standstill than at the transition point and as low as the square root of the ratio between the absorption of the torque at standstill and torque absorption at the transition point. Other factors than those mentioned, which have some influence, have been found to be so small compared to the variation in rh that these factors are included within the limits for the curves defined by the formulas.



   In connection with the previous discussion, it is furthermore desirable to point out that a change in the exit angle of the blades of the turbine, in particular those of the last stage of the turbine, also influences the absorption characteristics of the turbine. input torque of converters. If the exit angle of the blades of the last stage of the turbine is increased, there will be a tendency to decrease the value of the torque absorption of the converter from standstill to the point of transition and vice versa.



  However, the effect of varying the exit angle of the blades of the last stage of the turbine is less for a relatively high prior of the rh / ra ratio than for

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 lower values of this ratio.



   With fin arrangements according to the present invention, a greater variation than heretofore in the exit angle of the fins of the last stage of the turbine is possible for the manufacturer, to satisfy specific conditions. This angle will preferably not be less than about 20 as a lower limit but may in some more or less extreme cases be 90 or even more, the latter case providing what can be considered a negative exit angle. * Usually, the upper limit will not exceed approximately
55.



   With a converter having the characteristics provided by the principles discussed above, consideration will now be given to the nature of the improved results obtained in a prime mover, as a whole, which combines such a converter with an internal combustion engine of the type having an internal combustion engine. relatively wide speed range and having, on the other hand, an output torque characteristic which produces a substantially decreasing torque from a maximum value which occurs substantially at the middle speed of the speed range, up to a value substantially lesser, which occurs both at low speed and at the rate at which maximum power is developed.



   In the preceding discussions, the various factors and characteristics have been considered on the basis of the operation of the converter at a constant speed of the input shaft, but as will already be understood the object of the invention is a converter and a prime mover giving rise to the operation of a vehicle, which will make use of highly variable speeds of the input shaft. In connection with the following discussion concerning the relation of

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   cooperation between @@ converter according to the invention and an internal combustion engine with variable torque and variable speed, it should not be forgotten that, all other conditions being equal,

   the torque absorption characteristic of a converter of the kind considered is such that the torque absorption for a given ratio n2 / n1 varies substantially as a function of the square of the speed of the input arter.



   In order to illustrate more clearly the nature of the performance obtained, there is shown in FIG. 1 f a diagram giving the characteristics of horsepower, torque and fuel economy of an internal combustion engine. known eight cylinder 324 cm3 with a stroke in inches of (3-1 / 4 "x 4-7 / 8) in commercial production. In this figure, the number of revolutions per minute has been plotted on the abscissa. (RPM) of the engine (in hundreds of revolutions) and in order the power in horsepower at the brake (BHP), the torque (T) in feet / pounds and the fuel consumption (FR) in pounds per power and hour Curve A relates to torque, curve B to power and curve C to fuel consumption.

   It can be seen from the diagram of Figure If that maximum power is achieved at 3200 rpm, while maximum torque of 240 ft / lb is obtained at 1000 rpm;:; per minute, the value of the torque dropping to 185 feet / pounds at 3200 revolutions per minute and at this same value at about 500 revolutions per minute.



   The type of engine illustrated is suitable for propelling vehicles with a transmission in which a direct mechanical control is used alternatively with a nar converter control. In these commands ,. there is always what can be called a "vehicle transition or change point", which occurs when, during full throttle operation of the engine, a glare.

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 Higher motor speed with con @ erti @ - sour control would be less advantageous than a direct one hundred wave transition or transition.

   This transition point always occurs when the ratio of speeds n2 / n1 in hydraulic control is less than 1 and, when switching to direct control, the ratio of speeds n2 / n1 divides equal to the unit, so that the motor speed is reduced, when the transition or the change to direct control is carried out. With an engine whose torque curve rises, as the speed decreases from full speed, the proper transition point of the vehicle is for an he / he ratio developing in the converter a torque multiplication which is equivalent to the increase in engine torque caused by the reduction in engine speed resulting from the change or transition to direct drive.

   With such a transition point, the power supplied by the driven shaft in the converter drive just before the transition and in the direct drive just after the transition will therefore be approximately the same.



   If we now consider the motor, the characteristics of which have been given above, the suitable application of a following typical converter, the present invention would require, for example, with respect to a suitable transition point , a structure, in which the ratio of the secondary torque to the primary torque (M2 / M1) would have a value of about 1.26 for a gear ratio il 2/111 of about 0.68 and an endurance of about 84% for this gear ratio. a two-stage converter having these characteristics can be easily obtained by practicing the following known principles of construction.



   If we assume that to the motor mentioned above is connected a converter having dimensions teller that it can absorb a power of 115 horsepower at a r

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 speed port n2 / n1 of 0 'OD, 5 the power supplied to the shaft driven by the converter, when the engine is running at 3,200 rpm and developing a power of 115 horsepower, will be approximately equal to 9o horses.

   When the change to direct drive is made at this transition point, the engine speed, assuming the vehicle speed constant, will drop to 2,200 rpm, with the engine developing approximately 96 horsepower and, since the direct drive has about 100% efficiency, the power supplied to the driven shaft will be approximately the same as that developed by the hydraulic drive just before the transition is made.



   By combining a motor of the kind described, yes exhibits rapidly increasing torque as speed decreases from full speed, with a torque converter having characteristics in accordance with the present invention, and allowing In using such an engine effectively, the advantage is obtained that the vehicle's transition point can be obtained in an operating condition of the converter where the latter still produces a torque multiplication, rather than a gear ratio. higher than n2 / n1 where the converter has stopped producing any increase in secondary torque over primary torque.

   If, for example, an engine with a substantially flat torque curve were employed in the upper end of the speed range, little or no increase in engine torque would occur when switching to direct drive. compensate for the drop in engine speed caused by switching to direct control. Accordingly, in this case, the appropriate transition point should correspond to a point where there is substantially no torque multiplication in converter control.

   The reason for lanuellc it pst

 <Desc / Clms Page number 25>

 Advantageous that the transition point corresponds to a point where the torque converter produces a torque multiplication, is that ordinarily the converter runs from a point where it can produce a torque multiplication of about 1, 25: 1 to a point where no torque multiplication is produced, is relatively inefficient compared to running in which a higher torque multiplication is developed in the converter.

   Therefore ; As a result of being able to place the transition point at a point, where some torque multiplication is produced in the converter, high and low effective ranges of the converter n2 / n1 speed ratio are avoided.



   Assuming, moreover ,, that in accordance with the principle of the present invention, the converter is agen-. this so that the 'M1 stop / M1 transition ratio is equal to approximately 6.4, which in accordance with the curves shown in Figures 1c and 1g indicate a placement of the outlet edges of the fins of the last stage of the tubbine, of a share, with respect to the external diameter of the liquid circuit, so that the ratio rh:

  rc is approximately 0.70 and, on the other hand, relative to the entry edges of the fins of the pump. pe, so that the rh / ra ratio is approximately
1.25, the increasing torque absorption characteristic of the converter must be such that, if the drive is by the motor referred to above, under stop conditions, the speed of the motor will be reduced to approximately 1600 rpm from the speed of 3200 rpm, which represents the engine's full throttle speed at the transition point. With a converter of the type described here, it is easily possible to obtain a multiplication of the torque M2 / Mr of at least 3.5 when stationary.

   This torque multiplication combined with the increased neck

 <Desc / Clms Page number 26>

 Firing the engine from 185 ft / lbs at 3,200 rpm up to 240 ft / lbs at 1,000 rpm gives overall torque multiplication of about 4.75, which is an adequately high value for the transmission portion of the usual control of a vehicle and may, in certain cases, in particular in the case of passenger vehicles, be significantly greater than the necessary multiplication.



     In addition to the advantage obtained in this way, other important advantages are gained. By providing a converter which will reduce engine speed to as low as 1600 revolutions per minute when stopped, the unwanted rapid acceleration of the engine from idle to full speed. or substantially at full speed; when starting the vehicle, is avoided.

   Rapid acceleration of an engine to a high speed when starting is undesirable because of the inevitable noise and because this acceleration is detrimental from the standpoint of fuel consumption. In. now. the. engine speed at a low value 'at' start-up and during the early stages of vehicle acceleration, the engine operates on the most economical part of the specific fuel consumption curve, as is clear from figure If, and if the arrangement is of the type described above, it will be seen that from the stop, when the engine is running at 1600 revolutions per minute,

   the first 'acceleration will occur with an increase in engine speed over a range of speeds where the power produced by the engine increases relatively rapidly, even though the engine torque decreases slightly.



   In the previous discussion, it was assumed that use was made of a converter whose wings were annoyed so as to obtain a ratio! -Il stop / M1 ppor l stop 1 transition

 <Desc / Clms Page number 27>

 of 6.4. If desired, this value can, as previously reported, be easily increased to a significantly higher value, in which case the engine speed at standstill can be reduced to an even lower value. for example up to 1200 revolutions per minute.

   If this were the case, a somewhat less tractive effort would be obtained at standstill, but on the other hand the tractive effort curve would not fall as quickly, when the vehicle was initially moved from. of the stop, given that .; under these conditions, the engine would initially operate on an increasing part of its cutting curve.



   It follows from the previous description that, whatever the specific form of the converter when the fin system is arranged in accordance with the invention and when the converter is combined with an engine having certain specific characteristics of power and torque, many substantial advantages are obtained for traction control using a converter, which can have a relatively small structure and have a very low number of fin stages.



   The invention is applicable to many specific types of converter and Figure 2 shows a fin system incorporated in a converter having a rotating housing rather than a fixed housing with a direct drive shaft as in. Figure 1. As shown in Figure 2, the primary element or 'drive element 24 is constituted by a rotating housing, adapted to be connected to a motor (not shown) and to be driven by it. this. The casing carries the pumping fins 28.

   As for the disk 42 of the turbine, it carries the two stages of fins 34 and. 36, tanuis that the reaction fins 46 are carried by the reaction disc 50, as described above. In addition to a

 <Desc / Clms Page number 28>

 
 EMI28.1
 rotary carcer, the converter according to the present version 1 / ck differs from that described above, by L-fl. q,. the blades 34 of the first stage of the turbine are a, = '3:; r.>; - on the radial inlet side of the circuit, so that 0.68 longer wedges are provided for the pump.



   FIG. 3 represents, in the form of a more or less conventional diagram, the characteristics of the re-presented converter, in comparison with known types of converters, with regard to the ratio of the input and ser speeds. tie n2 / n1. In this diagram, the solid lines M1 and n2 indicate respectively the absorption characteristics of the input torque and the speed characteristics (} 'resulting input of the present converter, while the li- the broken lines M'1 and n'1 indicate the corresponding characteristics of what can be considered as a known conventional converter form.



   In the description of the discussion of the rprédentes embodiments, the nature and features of the invention have been considered without regard to. whether or not the reaction vanes 46 are, during the operation of the converter, unable to rotate in a direction opposite to that of the pump and the turbine, while no further consideration has been given to Whether the reaction fins 46 are incorporated into the apparatus in such a way, when the converter is operating, these reaction fins rotate in the opposite direction and in fact become movable reaction fins rather than control fins. fixed reaction and also operate, thanks to a gear connection,

   so as to transmit the torque to the driven element, these fins can therefore be considered as the horns of the reverse rotation or onoosed fins.
 EMI28.2
 l 'uti li? 3.tioll these turbine fins toiu'ir-at #!

 <Desc / Clms Page number 29>

 The opposite is generally known and, for ease of description, converters comprising such fins will be referred to, in the remainder of this specification, as being double-rotation converters, as opposed to single-rotation converters.

   in which the reaction fins are unable to rotate in the opposite direction.



   The present invention is particularly advantageous, when it is applied to converters with double rotation, for the reasons indicated later. Figures 4 and 5 of the accompanying drawings show, by way of example, an embodiment of the invention, in the form of a double-rotation converter, combined with such a direct drive.



   In FIGS. 4 and 5, the illustrated hydraulic circuit is contained in a structure of the rotary case type, in which the rotary case 24, which is driven by the flywheel 12 of the engine by a toothed connection or the like 32, carries the fins 28 of the pump. The turbine element 44, which is carried by bearings 58 and 60, has an impeller portion 42, which carries the two rows of turbine fins 34 and 36. Between these rows of fins, the row of turbine blades Reaction vanes 46 is carried by a disc 50 forming part of the reaction element having a hollow shaft part 48 to which is locked a hollow shaft extension 62.



  Between the driven shaft 44 and the extension 62 of the reaction element is mounted a freewheel coupling 110 arranged so that when the reaction element tends to rotate in the same direction as the element 44, the coupling comes into service, so as to prevent element 62 from passing beyond element 64, while still allowing free rotation in the opposite direction.

 <Desc / Clms Page number 30>

 posed relative between the parts.



   Element 62 also has sun gear 366 meshing with planetary gears 370, which in turn maintains a ring gear internally carried by element 368 wedged on driven element 44. Pinions 370 are carried by a support. 376. Between this support 376 and the fixed housing 16 is a freewheel coupling 378 arranged to prevent the support 37o from rotating in a direction opposite to that of the elements of the. pump and the turbine, while allowing the support 37b to rotate freely in the same direction as these elements.



   A multiple-disc fastening coupling is interposed between the rotating housing 24 and the reaction element. This coupling comprises a number of axially movable plates 270 wedged on the extension 122 of the rotating housing, as well as a number of intermediate plates 254 wedged asially on a bell-shaped extension 252 of the reaction element 48. The latter also carries a support plate 256, which cannot move in the axial direction, and a piston or action plate axially movable member housed in a suitable annular recess of member 252 and arranged to turn the coupling on or off under hydraulic pressure established in chamber 264 under the control of a valve element 350.



     The support element 350 is actuated so as to put the coupling in service or out of service by means of a fork 354 (see figure 5), mounted on a pivot and the action of which is controlled. by a system of actuators 352 and 362 actuated hydraulically and to which a pressurized fluid is supplied or from which a fluid under pressure is removed under the control of the axially metile valve 3 @ 6.

 <Desc / Clms Page number 31>

 



   The pressurized fluid to operate these servomotors and also to maintain a desired base hydraulic pressure in the converter circuit is supplied by a gear pump 380 driven by extension 122 of the rotary housing through the pinion. intermediate 384 meshing with pinions 386 carried by part 122 and with pinion 382 carried by the pump shaft
The outer periphery of the reaction member extension 252 constitutes a braking surface, on which a brake band 358 can fit, serving to prevent the reaction member from rotating. This brake is actuated by the intermediary of the band 360 and the actuating lever 364 by the upward movement of the piston of the servomotor 362 and is released by the action of the spring forming a part of this device.

   A spring device 410 is provided to move the brake band away so as to prevent further resistance being offered when this band is released.



   The action of the arrangement of the servomotors is such that, when the valve 396 is brought to position a, pressurized fluid is not admitted to the coupling 250, so that the latter is released and that, therefore, the rotating housing is disconnected from the reaction element.



  In this position of the control valve, the brake band 360 is released, so as to allow the reaction member to rotate freely in either direction, with respect to the brake. Under these conditions, it will be seen from a reference to figures la and lb that the reaction fins will rotate in the opposite direction with respect to the turbine fins 34 and 3b, it being understood that, in the present construction, the fins of the first stage of the turbine are on the radial inlet side of the circuit, rather than

 <Desc / Clms Page number 32>

 
 EMI32.1
 to extend radially outside the 2U spandrels on the ... pump, as in the arrangement of fins shown au- ;: iM ".; * res 1 and 2.

   This state of affairs ensures a double-rotation operation of the converter, the torque came from the reaction fins in the opposite direction, which in fact constitute under these conditions, also turbine fins, both transmitted through the reaction element and pinions 366,370 and 368 to the driven member 44. The nature of the torque developed is such that it will tend to rotate the planetary carrier 376 in a direction opposite to that of the driven member, but this is prevented. by the action of the coupling 378. If the valve 396 is brought to position b,

   the resulting action of the servomotor system will be to bring the band 358 into contact with the surface of the brake drum on the extension 252 of the reaction element and to prevent the latter element from rotating, while not allowing at the same time from the actuating fluid to the coupling 250. Under these conditions the fins 46 become stationary reaction fins and the converter operates as a single-rotating converter. When the reaction element is blocked. against any rotation, the sun gear 266 of the planetary gear is fixed, while the ring gear connected to the driven element continues to rotate forward.

   This of course requires that the support 368 also rotates forward and this action is enabled by the free-rolling action of the action.
 EMI32.2
 '#ouIerient 37fi between the support and the stationary casing * If the 33 control upape is brought to the position, -; ": c, the servomotors act in such a way as to release at nOUY9i" 1 brush 358 and also act from a: : 3? 1i'g à actiomior 1.t {} J :: r-> nt 354, so that the valve 350 is dol.'c'o '. ,,. l.'s. -'t: = ':; ¯f: l'V:

  .It21 consider figure 4) and ou'.ri i'L'-r.

 <Desc / Clms Page number 33>

 under pressure is therefore admitted into the shaft 264 behind the actuating plate 258 of the coupling 250, which is thus put into service * This serves to mechanically connect the rotating housing directly to the ele. - reaction element, which in turn transmits energy mechanically to the driven element 44, via the coupling. freewheeling 110.

   Since, under these conditions, the reaction element and the driven element move at the same speed in the forward direction, there is no relative movement between the gears of the system. gearing: planetary, which is allowed to rotate forward as a whole, under the effect of the driving action of the freewheel coupling 378. Since the brake band 358 is released , the entire coupling is also free to rotate.



   With respect to the present invention, any specific form of coupling and any mode of actuation thereof can be made.



  Accordingly, the servo motor system for operating the coupling is not described here in any detail other than that necessary to understand the operation of the transmission shown, in order to provide double rotation, single rotation and direct order.



   With regard to the specific hydraulic circuit shown in figure 4, it is obvious that it applies the principles discussed above with reference to figures 1 and 2.



  Moreover, it is obvious that the specific structure shown in figure 2 can easily be incorporated into the organization shown in figure 4.



   In Figures 6 and 7, another embodiment of a double rotation converter applying the principles of the present invention is illustrated. Construction

 <Desc / Clms Page number 34>

 of this embodiment is similar in all respects to that shown in Figure 4, except for the arrangement of the planetary gear connecting the reaction and turbine elements, so that it is not It is not necessary to describe this embodiment in detail. In this
 EMI34.1
 here, the extension: slow 252 of the reaction elements., x: -te an annular rim, yes extends in the axial direction and forms a ring gear 504 meshing with pinions 500, which are carried by shafts 502 s 'extending from the fixed housing 16.

   The pinions 500 mesh with a sun pinion 512. Between this pinion and the driven element 44 is a freewheel coupling 514. This coupling 514 is arranged so as to allow the pinion 512 to rotate in direction. opposite to driven member 44 and acts to prevent pinion 512 from passing driven member 44 in the same direction
In the operation of this form of transmission, position a of valve 596 results in the coupling 250 and brake 258 being deactivated, so as to allow the reaction vanes to rotate in the opposite direction. - pour.

   The torque supplied by these vanes is transmitted through the reaction element to the pinion 504 and through the pinion 500 the direction of the drive is reversed, so that torque is applied by the coupling 514 in the direction of the drive. forward direction to the driven element, which assures dual rotation operation. Under weight b of valve 596, fr-in 358 cooperates with element 252, so as to prevent any rotation of the reaction element and to ensure simple rotation of the converter. When the reaction element is locked against rotation, the pinions 500 are also unable to rotate about their individual axes, while the sun pinion 512 is also incapable of turning.

 <Desc / Clms Page number 35>

 turn.

   This pinion may, however, remain stationary, while the driven member 44 rotates forward, due to the driving action of the coupling 514.



   The movement of the control valve 596 to position c has the effect of releasing the brake 358 and admitting pressurized fluid into the coupling 250, which is thus put into service. Under these conditions; - the reaction element, which is now mechanically connected to the rotary housing, directly transmits energy from the latter to the driven shaft via the coupling 110, which is arranged so as to operate, when the reaction element tends to pass the driven element in the same direction.

   Under these conditions, the crown, toothed 504 carried by the reaction element turns towards II before and, by means of the pinions 500, turns the sun gear 502 in the direction opposite to that of the driven element, this being enabled by the action of coupling 514.



     As noted above, the principles of the invention are particularly advantageous when applied to a converter capable of double-rotating operation. This is due to the fact that it is inherently possible to obtain a higher torque multiplication rate (M2 / M1) with a double-rotation converter than with a single-rotation converter, all others conditions being equivalent.

   In short, the reason for this is that in any torque converter the secondary torque M2 should always be equal to the sum of the primary torque M1 and the reaction torque R1 transmitted to the fixed case or other element. fixed. In the case of a single-rotation converter, the reaction torque R1 transmitted to the fixed element is equal to the torque R, which is applied to hydraulic

 <Desc / Clms Page number 36>

 only by the working fluid to the reaction fins.



  However, in the case of a double-rotation converter, the torque R1 transmitted to the fixed element is equal to the torque R added to the value of the torque R multiplied by the gear ratio (which will be designated by k) . Thus, all other conditions being equivalent, the value of N2 at standstill serc for example, greater with a double-rotation converter than with a single-rotation converter * As an example of the difference in the torque ratios obtained - adjustable when stationary with the two types of converters, it can be noted that with the torque converter with single rotation and three stages, exhibiting an acceptable efficiency and. other characteristics, the maximum torque ratio at the stop that is usually obtained is in the order of 5: 1 6: 1.

   Theretically, with a double-rotated converter an extremely high torque ratio can be obtained at standstill, if other desirable characteristics are sacrificed, but with converter types ensuring satisfactory efficiency and characteristics. on the other hand, torque ratios on the order of 12: 1 at standstill can be easily obtained in a two-stage converter.



   In view of the high torque ratio which can be obtained at standstill with a double-rotation converter, the particular advantage of a torque converter applying the principles of the present invention lies in the fact that with a high torque ratio established when stopping a converter and with a high value of the M stop / M2 transition ratio also established in the converter by a relatively high ratio of rh / rc or rh / ra, these the latter characteristics can be used to reduce the speed of the motor, when stationary, to a very low value, which can even be equivalent to that of

 <Desc / Clms Page number 37>

 ordinary che empty in extreme cases.

   One will suppose for example that the normal maximum speed of the engine is 3600 revolutions per minute and that the converter is established with a .il stop / M- transition ratio having the effect of reducing the speed of the stationary engine to 1200 revolutions per minute. minute. This reduction in engine speed will obviously have the effect of reducing its power at standstill, compared to its power at full speed, but due to the fact that the double-rotation converter can easily provide multiplication. With a torque cation of the order of 10 or 12 or even more to 1, the desired fraction force can be obtained at a standstill, even if the engine is running at a relatively very low speed.

   Thus, with this arrangement, a more or less standardized simple converter can be adapted or combined with motors having highly variable characteristics, so as to provide the desired tensile forces, given that thanks to the simple expedient consisting in adjusting the gear ratio between the double rotating parts and also consisting in adjusting the rh / rc or rh / ra ratio, the converter can acquire torque absorption characteristics and stationary torque characteristics, which reduce the speed of a given engine, when stationary, to a specific value desired to obtain fuel economy and other best operating characteristics,

   while at the same time providing satisfactory characteristics for the traction of the vehicle.



   As noted above, the difference between the arrangements shown in Figures 4 and 6 lies primarily in the transmission between the reaction element and the driven element. In the example shown in FIG. 4, the renctio fins 46 are connected to the solar pinion 366, the diameter of which is approximately equal to the

 <Desc / Clms Page number 38>

 half the diameter of the ring gear 368 connected to the driven element or the turbine element 44.

   Thus, the ratio k of the transmission is 2.0, so that the value of the reaction torque and therefore the secondary torque M2 is higher than in the case where the fins 46 are not connected. so as to give a multiplied torque.



  In the embodiment shown, by way of example, in FIG. 6, the reaction fins 46 are connected to the ring gear 504, the diameter of which is substantially equal to the double of the diameter of the sun gear 512 connected to the turbine element. In this example the transmission ratio is 0.5 and, although the torque actually applied hydraulically to the vanes 46 is, in this example, reduced in value before being applied to the reaction elements. - tion and driven, the total torque multiplication is even greater than with a single-rotation converters, due to the value of R xk, which is a factor added to the determining factors of the multiplication of torque in a single-rotation converter,
Thus, in the example of transmission illustrated in FIG. 4,

   the torque multiplication at standstill will be greater than with the arrangement shown in FIG. 6, all other conditions being equivalent. Moreover, other factors than the ratio of torques at standstill are influenced by a variation in the ratio r. In the case of the embodiment illustrated in FIG. 4, the transmission ratio is such that the reaction fins 46 rotate, in the opposite direction, at a speed double that at which the turbine fins 34, 36 turn forward. In this case, the efficiency increases relatively quickly from the stop, as the value of n2 / nl increases.

   Likewise, the ef-

 <Desc / Clms Page number 39>

 The efficiency of the converter in the double rotation drive reaches its maximum and decreases relatively quickly to a relatively small value of n2 / n1, so that the desirable transition point between the double rotation drive and the single rotation drive occurs at a relatively low value of n2 / n1, which usually indicates a relatively low vehicle speed.



   In the case of the transmission shown in figure 6, in the double-rotation mode, the reaction vanes rotate in the opposite direction to the fins 34,36, but at a speed corresponding to half that of the fins mentioned last. location. In this case, the efficiency of the converter increases more slowly as the value of n / nl increases from standstill and the peak efficiency is obtained, in the double rotation mode, at a higher value. of n2 / n1, so that the appropriate transition point between the double rotation control and the single rotation control will occur at a value of n2 / n1 and at a speed of the vehicle. higher than with the arrangement shown in Figure 4, all other factors being equivalent.



     It will thus be seen that the choice of the specific transmission ratio to be employed will be dictated by considerations such as the maximum torque ratio desired at standstill and the shape of the efficiency curve as a function of the variation of the speed. value of n2 / n1 in individual cases.



   In FIG. 8, the nature of the efficiency curves obtained with double rotation converters, such as those shown in FIGS. 4 and 6, has been represented more or less conventionally. In this figure, the secondary torque is indicated by the curve M2, the efficiency in rotating operation doubled by a, the efficiency in rotating operation sim

 <Desc / Clms Page number 40>

   ple by b, the efficiency in direct control by c and the primary speed characteristics by ml.

   If, for purposes of comparison, the curves shown in Figure 8 are taken to represent the action obtained with a converter of the type shown in Figure 4, the effect obtained by reducing the rate of transmission to 1 as shown in figure 6, would be to decrease the value of M2 at standstill and move the maximum of curve a to the right as shown in figure 8, so as to place the point of maximum efficiency of this curve at a higher value of n2 / n1.



   Although for the purpose of illustrating the principles of the invention in their application to single-rotation and double-rotation type converters, specific forms of double-rotation converters have been described comprising rotating housings, as well. that means for ensuring a step with simple rotation and a direct control provided in a particular way, the invention is not limited to these specific embodiments. Thus, the type of hydraulic system with a fixed housing and a direct drive shaft illustrated in FIG. 1 can easily be combined with a tram mission of the type shown in FIGS. 4 and 6, so as to allow both double rotation step and one single rotation step.

   It also goes without saying that, if we so desire. re, single-turn operation and / or direct control can be omitted. for
Moreover, although for reasons of simplicity and minimum cost, it is preferable to use two-stage converters of the illustrated type, which converters are satisfactory in most cases, the principles of the invention are everything. also easily applicable to converters with a greater number of turbine and reaction fin stages.



   It follows from the preceding description that the in-

 <Desc / Clms Page number 41>

 The invention can be applied in many different mechanical designs and that, if desired, some elements can be employed to the exclusion of others. It follows !, that the invention should not be considered as limited to the embodiments described above by way of example, but should be considered as encompassing within / its scope all structures falling within the scope of the claims. - following instructions.



   CLAIMS.-
1.- prime mover comprising, in combination with an engine producing a substantially increasing output torque as the engine speed decreases in the upper part of the normal engine speed range, a hydrodynamic torque converter including a circuit comprising a primary element carrying pump vanes and driven by the motor, a reaction element carrying reaction vanes and a secondary element carrying turbine vanes arranged to rotate in the same direction as the pump vanes , the turbine fins comprising a row of fins, supplying working fluid directly to the inlet of the pump fins,

   the radial distance between the outlet edges of the fins of the aforementioned row and their axis of rotation being greater than the radial distance between the inlet edges of the fins of the pump and their axis of rotation, while the ratio between these distances rrdiales is such that the torque absorption capacity of the converter increases as the speed of the secondary element relative to the speed of the primary element decreases to a value of the speed of s. stop, the secondary element, which is several times greater than the value obtained when the speed of the secondary element relative to that of the primary element is

 <Desc / Clms Page number 42>

 such that the converter does not produce an increase in torque.



   2.- Driving machine comprising in combination with an engine producing a substantially increasing output torque when the engine speed decreases in the upper part of the normal engine speed range, a hydrodynamic torque converter comprising a circuit comprising a primary element carrying pump vanes and driven by the motor a reaction element carrying reaction vanes and a secondary element carrying turbine vanes arranged to rotate in the same direction as the pump vanes , the turbine fins comprising a row of fins directly supplying the working fluid to the inlet of the pump fins,

   the ratio between the outer radius of the last row of turbine blades and the outer radius of the working chamber being 0.5 to 0.8, which gives the torque converter an absorption capacity of torque which varies, during a decrease in the speed of the secondary element by increasing the speed of the primary element, up to a value of the speed, at standstill, of the secondary element , which is several times greater than the value obtained? when the speed of the secondary element relative to the glue of the primary element is such that the converter produces no increase in torque.



   3.- prime mover according to claim 1, in which the ratio of the radial distance between the outlet edges of the turbine blades supplying fluid to the rupture and their axis of rotation to the radial distance between
 EMI42.1
 tre 1 '"": bora .-- of entry of ailcttoc do L liI); ..) jf; t, 1 ',, -: \; 11 ni :.' ; ': i.;. 1l; 1.-U, r Ci!.' i'3rlS gifts a llttEr'T "#, Z i. !!!:). ti: t. <'i., - 1 - - 1, -i- or '<t? Ii' "rl¯rGI1 1.15.



  1; .-: .- chillj; notricc r; lliv; l1L la .I.trr "ltij ('1 ;;

 <Desc / Clms Page number 43>

 in which the turbine element carries at least two rows of fins between which is disposed a row of reaction fins.



   5. - Driving machine according to Claim 1, wherein the hydraulic circuit comprises a radial outlet part, in which the pump fins are located, and a radial inlet part; in which are the blades of the turbine discharging into the pump.



   6. A prime mover according to claim 1, comprising means operatively connecting the reaction fins to the driven element, for rotating the reaction fins in the opposite direction to the fins of the pump and to the driven element.



     7. A prime mover according to claim 6 comprising means for selectively maintaining the reaction element stationary or for releasing this reaction element so as to allow its rotation in the opposite direction.



     6. A driving machine according to claim 6, wherein the means ensuring the connection between the reaction element and the driven element consist of a gear comprising a, rtie for transmitting a reaction torque to a fixed element. and providing a gear ratio between said elements such that the reaction element rotates in the opposite direction at a speed greater than that at which the driven element rotates forward.



   9. A drive machine according to claim 6, wherein the means ensuring the connection between the reaction element and the driven element are constituted by a gear comprising a part serving to transmit a reaction torque to a fixed element and providing a gear ratio between said elements such as the reaction element

 <Desc / Clms Page number 44>

 rotates in the opposite direction at a speed slower than that at which the driven element rotates forward.



   10. A prime mover according to claim 6, comprising means for selectively keeping the reaction element stationary or for releasing this element so as to allow it to rotate in one or the other direction, while means are designed to provide a direct drive connection between the primary element and the secondary element
11.-Hydrodynamic torque converter comprising a circuit comprising a primary element carrying pump fins, a secondary element carrying turbine fins and a reaction element carrying reaction fins, the turbine fins being constructed so as to be rotated by the working fluid in the same direction as the pump fins and comprising a row of fins discharging working fluid directly to the pump fins,

   the outer edges of the row of turbine fins lying at a radial distance from their axis of rotation greater than the radial distance between the inlet edges of the fins of the pump from their axis of rotation.



   12. A converter according to claim 11, wherein the ratio of the radial distance between the outlet edges of the turbine fins supplying fluid to the pump and their axis of rotation to the radial distance between the inlet edges of the fins of the pump and the axis in question fall within an interval whose lower limit is approximately 1.15.



   13. A converter according to claim 11, wherein the fins of the row of turbine fins supplying fluid to the pump have an outlet angle of.

 <Desc / Clms Page number 45>

 taken between about 20 and 90.



     14. Converter according to claim 11, in which the ratio of the radial distance between the outlet edges of the turbine blades supplying fluid to the pump and their axis of rotation to the radial distance between the inlet edges of the pump. blades of the pump and the axis in question lies within an interval whose lower limit is about 1.15, and in which the fins of the row of turbine blades supplying fluid to the pump have a exit angle between about 20 and 90.



     15. A converter according to claim 11, in which the circuit comprises a radial outlet part in which the fins of the pump are located and a radial inlet part in which are located the fins of the turbine supplying fluid to the pump. the pump and in which the ratio of the radial distance between the outlet edges of the turbine vanes supplying fluid to the pump and their axis of rotation to the radial distance between the inlet edges of the vanes of the pump and the axis in question falls within an interval whose lower limit is approximately 1.15.



   16. Converter according to claim 15, in which at least two rows of turbine fins are provided between which is disposed a row of reaction fins.



   17. - Converter according to claim 11, comprising means operatively connecting the primary element and the secondary element, so as to rotate the reaction fins in the opposite direction of the primary element and the secondary element. .



   18. A converter according to claim 17,

 <Desc / Clms Page number 46>

 comprising means for selectively maintaining the reaction element stationary or for releasing this reaction element so as to allow its rotation in the reverse direction.



     19. Converter according to claim 17, in which the connection between the reaction unit and the secondary element is provided by a gear comprising a part serving to transmit a reaction torque to a fixed element and providing a gear ratio. gear between said elements such that the reaction element rotates in the opposite direction at a speed greater than that at which the secondary element rotates forward
20.

   - Converter according to Claim 17, in which the connection between the reaction element and the secondary element is provided by a gear comprising a part serving to transmit a reaction torque to a fixed element and providing a gear ratio. between said elements such that the reaction element rotates in the opposite direction at a speed lower than the speed at which the secondary element rotates forward
21. A converter according to claim II, comprising means for allowing the reaction element to rotate in the same direction as the primary element and the secondary element, as well as means for ensuring a connection between 'direct drive between the primary element and' the secondary element.



   22. - Hydrodynamic torque converter comprising a circuit comprising a primary element carrying the pump fins, a secondary element carrying turbine fins and a reaction element bearing reaction fins, the turbine fins forming a row of turbines. fins intended to receive the working fluid directly from the

 <Desc / Clms Page number 47>

 pump fins and a row of fins discharging from fin;

  ,. directly from the working fluid to the pump, these rows being arranged so as to be rotated by the working fluid, in the same direction as the fins of the pump, the reaction fins being arranged in the aforementioned circuit, so as to be attacked by the working fluid after it has discharged from the first-mentioned row of turbine fins and before it enters the second-mentioned row. turbine fins, while in addition the reaction fins are constructed so as to be rotated by the working fluid in a direction opposite to the direction of rotation of the pump and turbine fins, the converter also comprising means for transmitting torque from the reaction vanes forward to the driven element of the converter
23.

   - Converter according to claim 22, wherein the secondary element carries two rows of turbine fins, while the reaction element carries a single row of reaction fins arranged between the two rows of turbine fins *
24. A converter according to claim 23, wherein the first row of turbine fins are located in the radial outlet portion of the circuit, while the reaction fins and the second row of turbine fins are located. in the radial inlet part of the circuit, in the order mentioned above in the direction of flow of the working fluid.



   25. Converter according to claim 22., comprising means for selectively keeping the rotating element fixed or stationary or for releasing this element so as to allow this rotation.



     26.- Converter according to claim 22,

 <Desc / Clms Page number 48>

 in which the means for transmitting a torque from the reaction fins to the turbine fins are constituted by a gear comprising a part for transmitting a reaction torque to a stationary element, the converter comprising, moreover, means for maintaining selectively the reaction element fixed or to release it so as to allow it to rotate in either direction, as well as automatically releasable means associated with the gear, to allow the element to reaction to rotate in the same direction as the primary element and the secondary element.



   27.- Driving machine and hydrodynamic cutting converter, in substance, as described above with reference to the accompanying drawings.