ES2451491T3 - Cone and friction ring transmission, as well as an operation method of this type of transmission - Google Patents

Abstract

Friction ring and cone transmission, with an input cone, an output cone, and a friction ring surrounding one of the cones, as members (1, 2, 3) that rotate on each other transmitting a torque, and with a tightening mechanism to press said members (1, 2, 3), with means to capture a relevant magnitude, such as in particular the transmitted torque, and with means to apply a tightening force corresponding to one of the captured magnitudes, characterized because the tightening mechanism comprises at least two partial tightening mechanisms (9, 10, 11; 14), the first of which has a shorter response time than the second.

Description

Cone and friction ring transmission, as well as an operation method of this type of transmission

The present invention relates to a mechanism for tightening two members of a gear that roll over each other transmitting a turning moment.

These transmissions are known, for example, through patents of the same genus EP 0 878 641 A1 and EP 0 980 993 A2. In their second example of execution both documents reveal a clamping mechanism that, in

10 function of the moment of rotation transmitted by a conical outlet group belonging to the cone and friction ring transmission disclosed therein, applies a force with which the two cones are pressed, as well as the friction ring that rotates between them and surrounds the drive cone Thus, a sufficient tightening pressure can be ensured in case of high turning moments, avoiding the risk of slipping. In addition, patent EP 0 980 993 A2 reveals in its first example of execution a clamping mechanism whose applied force can be adjusted or adjusted from outside

15 by means of a hydraulic cylinder.

However, these mechanisms have the disadvantage that they need to have a comparatively high reserve clamping force, since the merely mechanical clamping devices respond with difficulty to the variations of the total operating parameters or react quite slowly to a regulation

20 external. In this regard, for mechanical clamping devices - which otherwise can only be adapted with many limitations to a desired characteristic curve - a reserve must be made that assumes changes in external parameters that the mechanics cannot capture immediately, while Tightening mechanisms controlled from the outside, due to the relatively long regulation times, need a reserve to be able to resist the tips of the turning moment.

The object of the present invention is to provide a transmission that provides advantages in this regard.

The present invention proposes as a solution a clamping mechanism, to press two members of a gear that roll over each other transmitting a turning moment, with means that record a parameter

30 relevant, in particular the moment of rotation transmitted, and with means that apply a clamping force depending on the registered parameter. This device is characterized in that it consists of at least two partial tightening mechanisms, the first of which has a shorter reaction time than the second. It is also proposed as a solution a transmission formed by two members of a gear that transmit a turning moment and are pressed by a corresponding clamping mechanism.

It is understood that such a device, constituted by two partial tightening mechanisms, can advantageously be used for the most diverse transmissions whose members must press each other according to certain parameters. All types of rotating transmissions with members that interact with each other by friction come into particular consideration here.

Preferably, the reaction time of the first partial tightening mechanism is chosen very short, so that it can respond quickly to blows or the like. Preferably, a purely mechanical configuration is chosen and therefore with almost no reaction time. In this way the tightening mechanism can be quickly adapted to brief oscillations, avoiding, above all, a slip between the transmission members that rotate one on

45 other.

In particular, it is enough to leave the first partial tightening mechanism unregulated and control it immediately only according to the critical parameters. In this way the first partial tightening mechanism - and therefore also the entire device - can be adapted very quickly and safely to shocks and variations almost

50 intermittent or discontinuous critical parameters. In this case, it is not necessary to optimize the first partial tightening mechanism with respect to its characteristic curve dependent on the parameter. It is more important that the first partial tightening mechanism can react to shocks and instabilities, especially in the shortest possible time.

A characteristic curve that is optimal for the entire device is preferably implemented through the second partial tightening mechanism, which may be optimized with respect to its characteristic curve or with respect to the characteristic curve of the entire device, without power or having to counteract Instantly bumps or sudden imbalances. It is especially advantageous that the second partial tightening mechanism is regulated so that the characteristic curve can be chosen as well as possible. In particular, the second partial tightening mechanism is

60 can regulate by means of the most different and diverse parameters, and therefore it can react in detail to the respective requirements. In addition, the partial tightening mechanism can be optimized with respect to vibration damping, especially in its regulating circuit, which also generally reduces response times. However - as stated above - this is not so critical, because the first partial tightening mechanism can react at respectively lower times.

A properly configured device according to the present invention can especially minimize the losses of a corresponding transmission. Above all, there is the possibility of optimally designing the first partial tightening mechanism considering safety and functional guarantee aspects, while the characteristic curve of the second partial tightening mechanism is chosen so that a displacement can be properly compensated

5 of the safety-derived characteristic curve of the first partial tightening mechanism.

Accordingly, the present invention, regardless of its other characteristics, resolves the aforementioned objective by means of a clamping mechanism to press two members of a gear that roll on one another by transmitting a turning moment, with means for recording a relevant parameter, in particular the transmitted turning moment, and with means to apply a clamping force according to the registered parameter, so that this device consists of at least two partial clamping mechanisms, the first of which provides a clamping force greater than or equal to the one that facilitates the complete device and the second one reduces the force of tightening contributed by the first one. Therefore, a transmission with two members of a gear which transmit a turning moment and are pressed by a corresponding tightening mechanism of this type is also advantageous.

15 In this type of configuration, the first partial tightening mechanism can excessively provide the necessary force, which makes it possible to absorb brief oscillations, ensuring operation. By means of the second partial tightening mechanism, excess force can be reduced, minimizing losses, without the risk that the tightening force is insufficient in case of short blows or the like.

Therefore, cumulatively or alternatively, it is advantageous that the second partial tightening mechanism exerts a force opposed to that applied by the first partial tightening mechanism. Thus the force can be reduced in an operationally safe way. In addition, with this configuration, the first partial tightening mechanism can spontaneously and directly depart from its characteristic curve and, if necessary, counteract the reduction in force

25 conditioned by the second partial tightening mechanism.

Preferably, the second partial tightening mechanism adequately compensates, in part, for the force exerted by the first partial tightening mechanism, which, if the configuration is suitable, is also advantageous, regardless of the aforementioned characteristics.

Although they are only used individually in a clamping mechanism or in a corresponding gear, these characteristics can significantly reduce losses if the clamping mechanism is optimized properly. In particular, the forces acting on the bearings, conditioned by the clamping forces, with which the respective gear members are housed in a frame or can be minimized

35 housing, which allows to avoid losses to a large extent. Here the prescribed provisions, especially the safety margins necessarily provided against unpredictable or rapid variations, can be reduced to a minimum, since the first partial tightening mechanism can react quickly or with sufficient force reserves. In contrast, during normal operation, the second partial mechanism preferably reduces the clamping force or the resulting pressure with the frame or the housing. This decreases the total losses, since blows or abrupt variations only occur briefly and are of little importance throughout the entire process time.

It is understood that a clamping mechanism according to the present invention can be used in the most diverse transmissions with gear members that roll over each other. Above all it is suitable for devices in

45 that the corresponding gear members interact with each other by friction or friction contact, with the risk of slipping in case of insufficient tightening force. With this type of tightening mechanism the loss in said devices can be minimized.

In a hydraulic system a corresponding tightening pressure can be applied by means of an electromagnetically controlled piston. This device occupies little space in a compact way and its mechanical construction is simple.

In its vertical stroke, the piston can first close an overflow / fill hole. This device or procedure ensures that there is always enough hydraulic fluid between the piston and the clamping mechanism. When

55 a force is exerted on the piston the liquid is compressed towards the tightening mechanism, until sufficient back pressure is created. When the piston is not pressed, excess liquid can escape through the hole and liquid can also be replenished from a reservoir when there is little left.

As an alternative to the hydraulic drive, a gear pump can also be provided. A gear pump for this application is relatively inexpensive and also has the advantage that it requires very little maintenance and works reliably, even with variable tightening pressures, due for example to oscillations of the rotation speed or the moment of rotation . Specifically, the gear pump can be driven by an electric motor, so that the moment of rotation preferably depends on the current. This can be achieved especially by limiting or regulating the current, which in a vehicle 65 is generally easier to implement than a voltage regulation. On the other hand, voltage regulation, especially digitally controlled, can be advantageous because it is easy to perform. So you can

provide a variable and tightening force in a simple and reliable way, without the need for the gear pump blades to be completely tight, since these - even by the way - can have some slack. In particular, for a drive that regulates the turning moment, the required clamping force can be guaranteed by a higher number of revolutions.

5 Instead of a gear pump, one of another type can also be used, especially a pump that similarly to the gear pump provides a pressure gradient or has an internal leak.

It is understood that these devices generating a variable tightening force are also advantageous for transmissions of continuous adjustment, such as those of cone and friction ring, independently of the other characteristics of the tightening mechanisms or gears, since they allow to ensure the respective optimum tightening pressure for a transmission of continuous variation by means of the adjustment stroke or the transmission ratio margin.

Cumulatively or alternatively an operation method is proposed for a friction transmission, with at least one input element and at least one output element that are pressed together by a clamping mechanism, which is distinguished because it operates according to a curve characteristic of work regime-force of tightening whose average slope between a state of rest of the transmission and a first regime of work is different from the one that presents between the first regime of work and a second regime of work. It is also proposed cumulative

or alternatively a friction transmission with at least two work regimes, where at least one input element and at least one output element are pressed together by at least one clamping mechanism whose force varies depending on the respective work regime, and that it is distinguished by a clamping mechanism with the characteristic work-force clamping curve already described above. This type of method or device allows to increase the efficiency of a cone and friction ring transmission during operation,

25 independently of the other features of the present invention.

This type of variant characteristic curve is especially advantageous for the tightening mechanism of all transmissions in which at least one input element and at least one output element interact with each other by friction. In this context, the term "friction" refers to any interaction without positive union between two rotating members of the transmission, so that preferably during excessively high turning moments a slack without destruction between both transmission elements can appear. This term also includes in particular an interaction produced by hydrostatic or hydrodynamic, electrostatic or electrodynamic or magnetic forces between both elements of the transmission. Accordingly, the present invention also relates in particular to friction transmissions in which a gap is filled by a fluid, for example a gas or

A liquid, between its corresponding mechanical members and the speeds, clearances, pressures and the like are sized in such a way that this fluid produces an interaction between both members of the transmission, for example by means of shear forces. In this sense, this variant characteristic curve is also suitable for those friction transmissions between whose members one or more means, such as fluids or even an additional member, are provided that promote interaction.

In all these devices the interaction between both members of the transmission is due in a large part to the forces acting on the respective surface involved of said members. For this, as is known from EP 0 878 641 A1 and EP 0 980 993 A2 for example, both transmission members can be properly pressed, which, for example, can be guaranteed by suitable bearings.

45 Likewise, as some practical examples describe in these documents, clamping mechanisms can be designed that, starting from a basic load, provide variable forces depending on the initial turning moment and therefore, if their initial values are high, they can also be generated. high clamping forces, which allows correspondingly increasing the moment of rotation that the friction gear can transmit. However, according to the technical state, these devices have high losses in such transmissions, which questions their efficiency.

As already mentioned, the input and output elements do not have to be united, but rather it is possible to think of the presence of intermediate transmission members or of means that facilitate friction joining, such as additional fluids or other interaction mechanisms. Due to the balance of forces prevailing in a transmission also

55 the input and output elements can be exchanged. However, as these transmissions are usually found in a complex drive chain, in general this differentiation must be maintained. It is also understood that a mutual back pressure of both members of the transmission can also take place by means of degrees of freedom of movement of said members, provided that at least one component of the degrees of freedom employed when pressing or squeezing is opportunely directed to the surface that interacts with a corresponding member of the transmission.

The friction ring transmissions according to the present invention can operate in various working regimes

or taking into account different types of work regime. These types of work regime can be, for example, moments of turning in and out, number of revolutions, forces and force ratios, pressures or

65 also temperatures, times or the like, and proportional magnitudes thereof. During the operation of a friction transmission such as the one mentioned above, in the different work regimes the corresponding type of regime is used and - depending on the specific form of execution or implementation - there are some regimes that are of minor importance or that are proportional to others easily measurable.

A variant characteristic curve can be performed cumulatively or alternatively, for example, with a transmission

5 of friction in which the tightening mechanism consists of at least two units. With such a clamping mechanism, consisting of at least two components, the characteristic work-force clamping curve can be adapted to the requirements with relatively simple means. This is particularly valid for the different average slopes of the characteristic work regime-tightening force curve described above. In this regard, the term “medium slope” defines a value between two work regimes or between a work regime and a state.

10 rest, which is calculated by averaging a slope or a straight line of the first section in the corresponding range of the characteristic work regime-tightening force curve. By varying the slope, the characteristic work regime-tightening force curve can be optimized, at least in two aspects according to the transmission requirements. In this way, the optimal possible relations between both work regimes can be sought, in terms of the driving force according to each specific work regime, choosing the clamping force in the way

15 as optimal as possible regarding the momentary work regime. Thus, the optimum friction transmission performance minimizes losses. On the other hand, the adjustment of the characteristic curve between the first working regime and the state of rest allows a direct transition between these two states and also minimizes the basic loads and losses. It is understood that these measures do not necessarily lead to an optimal result on their own, although this may be the case according to the existing limit conditions. However, the specialist obtains the possibility of

20 improve the efficiency of this type of friction transmissions. If necessary, a compromise is reached between additional measures to increase performance and, occasionally, higher costs.

Above all, it is advantageous for both component units of the clamping mechanism to have different characteristic curves of the working regime-tightening force. Combining both characteristic curves can be adjusted

25 correspondingly the overall characteristic curve of the clamping mechanism in a clear and understandable way.

Preferably both tightening units can respectively make a first contribution of force in the first work regime and a second contribution of force in the second work regime, so that the difference between the first and second contribution of the first divergent tightening mechanism of the difference between the

30 first and second contribution of the second tightening mechanism. Thus, a system is available in which the corresponding clamping units contribute distinctly to the total force of the mechanism in the respective working regimes, which allows a constructively simple influence on the characteristic curve of the entire clamping mechanism.

Regardless of the other features of the present invention, both clamping units can be configured to act in parallel or in series in terms of the establishment of the working regime and / or the clamping force. Thus, and also by suitable transmission ratios in the respective coupling, the overall characteristic curve of the clamping mechanism can be easily adapted to the requirements. It is true that with suitable curve paths or similar measures it is possible to adjust for this type of mechanism

40 a characteristic work-force tightening curve within relatively wide limits. But this in general has the disadvantage that external factors such as tolerances, play, thermal expansion or the like produce a displacement of the characteristic curve, so that it no longer has the correct path depending on the corresponding work regime. Specifically, in these cases it can no longer be guaranteed that a variation of the working regime will produce the desired variation of the clamping force. For this reason here is

45 proposes - also independently of the other characteristics of the present invention - that at least one clamping unit, preferably both or all, show a characteristic work-force clamping curve with a basically constant slope. This type of device is comparatively insensitive to the problems of tolerance or to the aforementioned disturbances, since each clamping unit is designed so that an external disturbance does not significantly affect and, thanks to the constant slope of the curve

In each case, a variation in the working regime caused by such disturbances produces the same variation in the corresponding clamping force. In this sense, such a solution is especially advantageous when friction transmissions with clamping mechanisms are used whose overall characteristic curve diverges from a straight line. In this context, the term “basically constant slope” should be understood as referring to the inevitable tolerances of the system and the other requirements of accuracy in the entire transmission shaft, for which reason

55 The idea of “proof” of a slope should not be considered more stringent than the total accuracy or tolerance of the system.

Preferably the clamping units are mechanically, hydrodynamically or hydrostatically coupled to each other, which is also valid for the case in which the clamping units are respectively separately in a

60 member of the transmission. Specifically, an initial load can be included in an input tightening mechanism or unit, especially by reducing the clamping force on partial loads, which allows to reduce the total losses of the friction ring transmission, so that this type The mechanism or clamping unit provided on the drive side is also advantageous, regardless of the other features of the present invention.

65 Likewise, the coupling of the input tightening unit to the output tightening unit makes it possible to reduce the clamping force under partial load in case of optimum performance of the total load and therefore minimize total losses.

5 As a working regime, several parameters of the corresponding friction ring transmission can be used. In particular they can be a moment of turning in or out, the total load, the incident forces or other parameters already mentioned above.

It is especially advantageous to control the moment of rotation of entry and / or exit, as well as of the total load, because from there you can obtain immediate information about the forces that affect the friction joint of both members of the transmission or that They are necessary for her.

Therefore, to compare the average slope between the state of rest and the first work regime or between the first work regime and the second work regime it is advantageous that the first work regime is the

15 the lowest expected turning moment under full load and the second working regime is the highest expected turning time under full load. Therefore, to properly dimension the characteristic curve, the necessary tightening force can be calculated for the least expected moment of rotation under full load and for the greatest expected moment of rotation under full load, so that the corresponding characteristic curve can be formed directly like a line between these two points.

The advantage of a straight line as a characteristic curve has already been explained in detail before. Similarly, a straight line can be drawn between the resting state or the minimum clamping force necessary for the transmission to start safely and does not slip or board and the clamping force necessary for the least expected moment of rotation under full load, thus taking advantage of the insensitivity to tolerance with the use of characteristic slope curves

25 constant. The choice of characteristic curve has the great advantage that a basic load is limited to the minimum necessary, so that the performance of such a friction transmission is also optimized in this regard.

It may be convenient to vary both tightening units by means of different types of working regime of the mechanism, as regards their respective force or contribution to the total tightening force. Thus, for example, the moment of rotation of the input or the total load of one tightening unit and the moment of rotation of the tightening force of the other can be varied. This makes it possible to adapt the overall behavior of the friction transmission, within a wide range, to the established requirements and therefore, above all, to optimize its performance.

Other advantages, features and objectives of the present invention are explained by the description based on the attached figures, which represent

Figure 1 a schematic section of a first transmission according to the present invention, with the clamping mechanism;

Figure 2 the outlet cone of a second transmission according to the present invention, with the clamping mechanism, represented analogously to Figure 1;

Figure 3 the exit cone of a third transmission according to the present invention, with the clamping mechanism, 45 represented analogously to Figure 1;

Figure 4 schematic representation of the relationship of forces in the embodiments according to Figure 1;

Figure 5 schematic representation of the relationship of forces in the embodiments according to figures 2 and 3;

Figure 6 schematic representation of the relationship of forces in an alternative;

Figure 7 schematic representation of the relationship of forces in a possible alternative;

55 Figure 8 schematic representation of the relationship of forces in another alternative;

Figure 9 schematic representation of the relationship of forces in another example of execution;

Figure 10 schematic representation of a section of the alternative referred to in Figure 6, analogous to Figure 1;

Figure 11 another embodiment of the alternative referred to in Figure 6, analogous to Figure 1;

Figure 12 schematic representation of a cut of another transmission, with an alternative tightening mechanism;

Figure 13 hydraulic regulation for a transmission according to the present invention; Figure 14 schematic representation of a section of a friction transmission according to the present invention; Figure 15 schematic representation of a detail of Figure 14;

5 Figure 16 schematic representation of the operation of the clamping mechanism of Figures 14 and 15; Figure 17 characteristic curve of the internal conical unit of the device according to Figures 14 and 15; Figure 18 characteristic curve of the external conical unit of the device according to Figures 14 and 15; Figure 19 characteristic curve of the complete clamping unit of the device according to Figures 14 and 15; Figure 20 alternative characteristic curve of the internal conical unit of the device according to Figures 14 and 15;

Figure 21 characteristic curve of the external conical unit of the device according to figures 14 and 15, adapted to the characteristic curve according to figure 20; Figure 22 characteristic curve of the complete tightening unit, taking into account the characteristic curves according to figures 20 and 21 of the device according to figures 14 and 15; Figure 23 possible characteristic curve of a clamping mechanism; Figure 24 another possible characteristic curve of a clamping mechanism; Figure 25 a particularly advantageous characteristic curve shape; Figure 26 a schematic representation of a section of a second friction transmission according to the present invention; Figure 27 characteristic curve of the input tightening unit of the device according to Figure 26; Figure 28 characteristic curve of the output tightening unit of the device according to Figure 26; Figure 29 characteristic curve of the complete clamping unit of the device according to figure 26; Figure 30 a schematic representation of a section of a third friction transmission according to the present invention; Figure 31 a schematic representation of a section of a fourth friction transmission according to the present invention; Figure 32 characteristic curve of the input tightening unit of the devices according to Figures 30 and 31; Figure 33 characteristic curve of the output tightening unit of the devices according to Figures 30 and 31; and 45

Figure 34 characteristic curve of the complete clamping unit of the devices according to Figures 30 and 31. The transmission according to Figure 1 comprises an input cone 1 and an output cone 2 that interact in the manner already known to each other by means of a ring of 3 adjustable friction. Here the input cone 1 is functionally connected with a drive shaft 4 and the output cone 2 with a drive shaft 5. In this exemplary embodiment the cones 1, 2 are radially supported by cylindrical roller bearings 6. Also in In this exemplary embodiment, the cones 1, 2 are tensioned together in an axial direction by means of four-point bearings 7A, in order to apply the necessary tightening forces so that the turning moment is transmitted by the friction ring 3 from the cone input 1 to output cone 2 and vice versa. In these figures the axial support of the cone of

55 entry 1 is not explicitly represented, but for example it can also be a four point bearing 7A

or an axial cylindrical roller bearing or similar.

To press or create the necessary clamping forces, a clamping mechanism 8 is also provided between the drive shaft 5 and the output cone 2, while in this exemplary embodiment the drive shaft 4 is connected to the input cone 1 directly. The clamping mechanism 8 can vary the axial distance between the output cone 2 and the bearing 7A of the drive shaft 5 and - when the device is tensioned - create the corresponding variable clamping forces.

It is understood that instead of bearings 6 and 7A, other types of support can also be used, such as angular angular contact ball bearings 65, spherical axial ball bearings, grooved groove ball bearings, tapered or analog roller bearings and combinations of these types of support, to support - by

one side radially and on the other hand sufficiently axially - the cones 1, 2 pressed. For example, hydrodynamic or hydrostatic bearings can also be used.

The friction ring 3 can be set in motion - in a known way but not detailed at this point - and choose

5 thus the transmission ratio. It is understood that during operation the entire device is or may be characteristically subject to different turning moments. Since the functional connection between both cones 1, 2 is friction, the clamping forces should preferably be high enough to dominate the sliding of the friction ring 3. On the other hand, unnecessarily high clamping forces would produce a basic load that is too high that would impair transmission performance. A controllable and, in particular, also sufficient slippage can be advantageous to facilitate the regulation of the transmission, because then only the number of revolutions is needed as a regulatory magnitude, while the turning moments are properly adjusted and transmitted by the tightening force .

In order to properly adjust the clamping force, in the present example of execution a regulation is chosen

15 depending on the turning time, although, as explained below, it can also be chosen based on other work regimes. In figure 1 it can be seen directly that the moment of exit rotation is chosen as the regulating magnitude of the clamping force.

In the present exemplary embodiment, the clamping mechanism 8 comprises two adjustment discs 9, 10 that have raceways for the balls 11, which on the one hand rest on the axis 5 by means of the adjustment disc 9 and on the other hand on the output cone 2 by means of the adjustment disc 10. For this purpose the adjustment discs 9, 10 are configured so that the turning moment is transmitted from the output cone 2 to the adjustment disc 10, by means of the balls 11 to the adjustment disc 9 and from there to the drive shaft 5. In this case the raceways of the balls 11 are configured so that a high turning moment produces a joint rotation of both

25 adjustment discs 9, 10 which in turn make the balls 11 move along the raceways, separating the adjustment discs 9, 10 from each other. In an idealized device, which in itself is rigid, does not movements are made; By means of oblique raceways, the turning moment produces an immediate increase in the clamping force. In this way the clamping mechanism 8 generates a clamping force depending on the moment of exit rotation.

This device has the advantage that as a clamping mechanism it has extremely short response times and, above all, it can react very well to blows on the output side of the drive shaft.

Parallel to the balls 11, the discs 9, 10 are separated from each other by a spring 12 which confers a certain basic load on the clamping mechanism 8.

Unfortunately, the characteristic curve of the device formed by the disks 9 and 10, as well as by the balls 11 and the spring 12 can only be optimized in a limited way. In this sense, the characteristic curve has parts in which the clamping force rises too much, which considerably increases the total losses of the corresponding transmission. For this reason, the device in Figure 1 has a force compensation, especially for partial load areas, which in this example is hydraulic. Between a disk connected to the drive shaft 5 and the clamping plate 10, a hydraulic pressure is generated that counteracts the clamping force exerted by the balls. In this way the excess or unnecessary clamping force generated by the balls 11 and by the spring 12 can be hydraulically compensated by exerting a counter force by means of a piece 13 firmly connected with the drive shaft 5. The respective relationships are schematically represented in the figure. 4, where the thickness

45 of the arrows reproduce the intensity of the corresponding forces. With the hydraulic pressure 14, excessive force of the balls 11 or of the spring 12 is compensated and therefore the bearings 6, 7A are not unnecessarily loaded. Here the arrow 90 indicates the external forces of the drive shaft 5, the arrow 91 the external forces of the output cone and the arrow 92 internal forces.

In the exemplary embodiment shown in Figure 1 the hydraulic pressure 14 is provided by a hydraulic pipe 15 located on an additional shaft 16 fixed to the axis 5 by means of a screw 17. Furthermore, the screw 17 closes a filling hole 18 which in combination with a pipe 19 and a rear narrowing 20 serves to fill the hydraulic space without bubbles, in a technically safe manner. At its opposite end to the drive shaft 5 the shaft 16 has a hydraulic joint, which allows the hydraulic pressure 14 to be formed and regulated easily from the outside.

55 desired.

Likewise, the device according to figure 1 has a mounting body 21 on which the conical exit group 2 is housed radially. With this mounting body 21, the clamping mechanism 8 can be easily mounted inside the conical exit group 2 .

The device shown in Figure 2 basically corresponds to the embodiment according to Figure 1, as it has components that act identically and also carry the same reference numbers; therefore they are not explicitly described again.

65 However, in this exemplary embodiment, the basic load is not generated by a spring connected in parallel, but by a spring 22 connected in series that rests on the drive shaft 5, in the present example of execution on a four-bearing points 23 which on the one hand transmit the tightening force between the adjustment disc 9 and the drive shaft 5 and on the other hand serve to axially accommodate the conical output group 2 with respect to the drive shaft 5.

5 Furthermore, contrary to the exemplary embodiment according to Figure 1, the hydraulic supply 24 reaches the inside of the conical outlet group 2, so that the corresponding joint 25 is located next to the part 13 firmly connected with the drive shaft 5 and hereinafter referred to as a counter disc 13. Therefore, by creating pressure in the pipe 26 of the feed 24 a hydraulic pressure 14 is formed between the counter disc 13 and the adjustment disc 10 which opposes the clamping force exerted by the balls 11, reducing the total clamping force of the mechanism 8.

As can be seen directly in Figure 2, in this exemplary embodiment the counter-disc 13 is threaded on the axis 5, while in the exemplary embodiment of Figure 1 an additional screw with the double function already mentioned above is used. The planned hydraulic space between the adjustment disc 10 and the counter disc 13

15 is sealed out by means of gaskets 27 (not shown in Figure 1).

As can be seen directly in figure 5, the device shown in figure 2 works in a similar way to that shown in figures 1 and 4. The pressure 14 also generates a compensatory force here and therefore allows the clamping force to be minimized total and with it the tension on the bearings 6, 7A.

For the second partial tightening mechanism, a motorized device can also be chosen instead of a hydraulic one, as shown in the exemplary embodiment of Figure 3, which otherwise corresponds to that of Figure 2 and operates as shown in figure 5.

25 This device also creates a basic load by means of a spring 22 connected in series, which is supported by a four-point bearing on the drive shaft 5.

To mount the motorized drive of the second partial tightening mechanism 14 there is a threaded bolt 28B in a bore 28A of the drive shaft 5, which is supported by a four-point bearing 29 on the adjusting disk 10 and in conical outlet group 2 , so that in this device the function of the threaded hole 28A corresponds to that of the counter disc 13. The threaded bolt 28B can be moved with respect to the axis 5 by means of a motor 30 - driven by an electric cable 32 and friction rings 33 - and a gear 31, which allows to create a variable force opposite to the tightening force exerted by the balls 11 and the spring 22.

As indicated in Figure 6, a device according to the present invention can also be implemented without a spring that generates a basic load. Figures 10 and 11 show schematized devices corresponding to the relationships according to Figure 6. Also here a clamping mechanism 8 is provided which has an adjustment disc 9 supported on the drive shaft 5 and raceways for the balls 11. However, in this case, unlike the exemplary embodiments according to figures 1 to 5, the raceways of the balls are provided in another adjustment disc next to the conical output group 2. Therefore the second Partial clamping mechanism 14 also splices directly with the conical outlet group 2 through a pressure chamber 34. Moreover, the operation corresponds to that of the exemplary embodiments shown above, whereby a detailed exposure is dispensed with. As a complement, it should be noted that in the exemplary embodiment according to Figure 10, the cones 1, 2 are supported by axial cylindrical roller bearings 7B. Also in this example

45, the second partial tightening mechanism 14 is preferably operated according to the moment of entry rotation, which is captured by the input shaft 4, an adjustment disc 35 attached to the input shaft 4, the balls 36 and a piston 37 which rotates jointly with the actuating cone 1 but can move axially, and is then transmitted hydraulically by means of a pipe 38 to the pressure chamber 34. In this case the pipe 38 is hermetically connected by through tubes 39 with the rotating components with cones 1, 2.

Apart from the regulation 40 of the moment of entry rotation formed by the components 35, 36, 37, the second partial tightening mechanism 14 can also be operated and regulated by a piston 41 as a function of other parameters.

55 A mechanical alternative to the embodiment of Figure 10 is shown in Figure 11, according to which, instead, the calculated input rotation moment is transmitted by means of a lever 42 to the second partial tightening mechanism. Furthermore, by means of a servomotor 43, other regulating quantities of the second partial tightening mechanism can be used.

The second partial tightening mechanism 14 or the complete tightening mechanism can be operated and regulated by means of different magnitudes, which can be in particular the torque, the number of input revolutions, the number of output revolutions, the travel or the adjustment position of the friction ring 3, the temperature of the transmission or an oil thereof, the number of turns of the wheels or for example the ABS signal (system

65 anti-lock), an external shock detection or other parameters.

As explained above, the corresponding measurement values can be transmitted hydraulically or motorized or by other means to the clamping mechanism 8. In hydraulic systems this can be carried out especially with pumps, for example with gear pumps or with pumps already existing in the vehicle and adequate pressure regulation. One can also think of piston devices and electric motor systems.

In particular, it is possible, for example, to provide a gear pump 61 driven by an electric motor 62 that brings fluid from a reservoir 64. In this case, by means of a current 63 supplied to the electric motor 62, a turning moment can be applied to the gear pump 61, rotating it so that the fluid or the tightening mechanism 8 generates a counter pressure corresponding to the pressure due to the moment of rotation.

A similar operation is shown in Figure 7, where the internal forces 92 are provided by balls 11 in parallel with a hydraulic pressure 14 and a spring 12 in series with them. The internal forces 92 oppose the external force 90 of the drive shaft 5 and the external force 91 of the output cone 2.

The alternative operation shown in Figure 8 carries a ball device 11 and a hydraulic pressure 14 in parallel with it, so that the balls 11 and the hydraulic pressure 14 produce internal forces 92. These internal forces 92 oppose the force external 90 of drive shaft 5 and external force 91 of output cone 2. Like the device of figure 6, the device according to figure 8 operates without additional spring.

In the exemplary embodiment according to Figure 9 there are balls 11, a hydraulic pressure 14 and a spring 12 connected in parallel for operation. Hence the internal forces 92 opposed to the external forces 90 and 91.

The transmission shown in Figure 12 comprises an input cone 1 and an output cone 2 that interact with each other by an adjustable friction ring 3. The input cone 1 is functionally connected with a drive shaft 4 and the output cone 2 is connected with a drive shaft 5. In this exemplary embodiment the input cone 1 rests on one side on cylindrical roller bearings and on the other side on tapered roller bearings 80. Tapered roller bearings 80 are especially suitable for absorbing axially acting forces, in addition to those acting radially. In this exemplary embodiment, the outlet cone 2 rests only on cylindrical roller bearings 6 and its drive shaft 5 also on tapered roller bearings 81. By means of tapered roller bearings 81, especially both cones 1 and 2 are tensioned together in axial direction, so that the necessary tightening forces can be applied to transmit the moment of rotation of the input cone 1 to the output cone 2 and vice versa by means of the friction ring 3.

To tighten or generate the necessary clamping forces, a clamping mechanism 8 is also provided between the drive shaft 5 and the output cone 2, while in this exemplary embodiment the drive shaft 4 is also directly connected with the cone of inlet 1. In this example of a device, the clamping mechanism 8 can also vary the axial distance between the outlet cone 2 and the tapered roller bearings 81 and - when tensioned - generate the corresponding variable forces.

As stated above, it is understood that the bearings 6, 80 and 81 provided in this exemplary embodiment can also be replaced or combined with other types of bearings, in order to support - on one side radially and on the other hand sufficiently in axial direction - cones 1 and 2 pressed. Also here hydrodynamic or hydrostatic bearings can be used.

The transmission ratio of the device illustrated here is selected by a displacement of the friction ring 3, which allows various forces to act on the assembly, especially various turning moments. In order to conveniently adjust the clamping forces, and therefore the friction joint between both cones 1 and 2, to the various operating conditions, the clamping mechanism 8 comprises two adjustment discs 9 and 10 with raceways for the balls 11. The adjustment discs 9 and 10 are configured so that the turning moment is transmitted from the conical output group 2 to the adjustment disc 10, by means of the balls 11 to the adjustment disc 9 and from there to the drive shaft 5 In this case, the raceways of the balls 11 are designed so that a high turning moment produces a joint rotation of both adjustment discs 9 and 10 and this in turn the balls 11 move along the raceway, whereby the adjustment discs 9 and 10 are separated from each other by tension. Ideally there are no movements between both adjustment discs 9 and 10 when the device is basically rigid. The turning moment produces an immediate increase in the clamping force by means of oblique raceways. In this way the clamping mechanism 8 generates a clamping force depending on the moment of exit rotation. Especially advantageously, the mechanical device described here has extremely short response times and, above all, is capable of reacting very well to blows on the output side of the drive shaft.

Parallel to the balls 11, the adjustment discs 9 and 10 are separated from each other by means of a spring 12 that provides a certain basic load to the clamping mechanism 8. Since the characteristic curve of the present clamping mechanism 8 can only be optimized limitedly, It has a force compensation, especially for partial load areas. In this exemplary embodiment, this is done by hydraulically creating a pressure between a plate of the adjustment disc 10 attached to the drive shaft 5, which opposes the clamping force exerted by the balls 11 and the

spring 12. In this way, the excessive or unnecessary tightening force exerted by the balls 11 and the spring 12 can be hydraulically compensated.

The pressure is provided by a hydraulic pipe 15 located on an additional shaft 16. Between the clamping mechanism 8 and the outlet cone 2 there is an oil chamber 82. By means of the oil contained in this chamber 82, centrifugal forces are better compensated than they act especially on the oil in the tightening mechanism 8. In order to have a sufficient amount of oil to regulate the tightening mechanism 8 a tank 64 is provided. In this case, by means of a current 63 applied to the electric motor 62, it can transmit a turning moment to a regulated pump 61 so that the fluid or the tightening mechanism 8 generates a counter pressure opposite to the pressure due to the turning moment.

The example represented in Figure 13 is an ideal alternative. In it, by means of a spacer 45 inside a housing 44, a coil 46 is provided which includes a core 47 with a piston 48 which is pressed towards the housing 44 by a spring 49. By applying a current to the coil 46, the core 47 is pressed towards the center of the coil 46 against the force of the spring 49, so that the piston 48 travels in a cylinder 50, creating in this cylinder 50 and in a pipe 51 connected thereto a variable pressure that depends on the current applied to the coil 46. The pipe 51 may be connected, for example, to the supply 26 of the exemplary embodiments according to Figures 1 and 2 or to the tubing 38 of the exemplary embodiment according to Figure 7.

In the cylinder 50, a hole 52 is provided, which first closes tightly as the piston 48 advances. This hole 52 is connected to an overflow / filling tank 53, so that when the entire device is not tensioned, it can be filled or filled with hydraulic fluid, for example to compensate for a leak or an overpressure due to external factors. It is understood that this type of electric drive of a hydraulic and / or leakage safety piston can also be used advantageously regardless of the other features of the present invention.

The friction transmission shown in Figures 14 through 22, including its characteristic curves, has an input cone 101 and an output cone 102 that interact with each other by an adjustable friction ring.

103. In this case the input cone 101 is functionally connected with a drive shaft 104 and the output cone 102 with a drive shaft 105. In this exemplary embodiment, the cones 101, 102 are radially supported by ball bearings. cylindrical rollers 106 (only schematically shown in Figure 14). Also in this exemplary embodiment, the cones 101, 102 are also tensioned together in axial direction by cylindrical roller bearings 107, which allows the necessary tightening forces to be applied to transmit the moment of rotation of the inlet cone 101 to the outlet cone 102 by friction ring 103.

To tighten or generate the necessary clamping forces, a clamping mechanism 108 is also provided between the drive shaft 105 and the output cone 102, while in this exemplary embodiment the drive shaft 104 is directly connected with the input cone. 101. The clamping mechanism 108 may vary the axial distance between the exit cone 102 and the tapered roller thrust bearings 107 on the drive shaft 105 and

- when the device is tensioned - generate the respective variable clamping forces by means of a spring 109.

It is understood that instead of bearings 106 and 107, other types of support can also be used, such as angular angular ball bearings, spherical thrust ball bearings, grooved groove ball bearings, tapered or similar roller bearings and combinations thereof types of support, to support on the one hand radially and on the other hand sufficiently axially - the cones 101, 102 pressed. For example, hydrodynamic or hydrostatic bearings can also be used.

The friction ring 103 can be set in motion - in a known manner but not detailed at this point - and thus choose the transmission ratio. It is understood that during operation the entire device is especially subject to different turning moments. Since the functional connection between both cones 101, 102 is friction, the clamping forces should preferably be high enough to dominate a sliding of the friction ring 103. On the other hand, unnecessarily high clamping forces would produce a basic load that is too high that would impair transmission performance. For this reason, in the present example of execution, a regulation of the clamping force depending on the turning moment has been chosen, although the clamping force can also be chosen according to other work regimes. In figures 14 and 15 it can be seen immediately that as the regulating magnitude of the clamping force the moment of exit rotation is chosen, although in this respect other work regimes can also be used, for example the total load or the moment of rotation input, as clarified by the execution examples described below.

In the present exemplary embodiment, the clamping mechanism 108 comprises two units 110 and 111 connected in parallel for measuring their turning moment and in series for the effect of their clamping force, which are respectively represented by internal balls 112 and external balls 113 (see Figure 15). The balls 112, 113 move respectively in raceways provided in the pressure plates 114, 115 and 116 on the cone side

or shaft. In this exemplary embodiment, the pressure plates 114 and 115 on the shaft side rotate in solidarity with the drive shaft 105, while the pressure plate 116 on the cone side rotates in solidarity with the conical outlet group 102. On the other hand Pressure plates 114, 115 and 116 can be axially supported on these components by appropriate bearings.

Thus, while a turning moment of the conical outlet group 102 is transmitted by the bearing 119 to the pressure plate 116, hence by the balls 112, 113, as well as the pressure plate 115 and the bearing 118, to the plate of pressure 114 and of this by means of the bearing 117 to the drive shaft 105, the pressure plates 114, 115, 116 are

5 can move axially against the force of the spring 109 and against a pressure support 120 supported on an axial cylindrical roller bearing 112 and a bearing base 122 in the conical outlet group 102, thus creating a clamping force dependent on the moment of turn depending on the characteristic curves. In this regard, figures 14 and 15 show on the upper edge of the clamping mechanism 108 the arrangement for a low turning moment, while the lower part represents the arrangement for a high turning moment, since at the bottom it is seen that for higher turning moments the pressure plate 116 rests on a flank 123 of the conical outlet group 102. Therefore, depending on the turning moment, the characteristic curve of the entire device can be easily influenced.

Figure 16 schematically shows in two-dimensional form the interaction of both clamping units 110 and

15 111. In it the components that have the same function as in Figures 14 and 15 bear the same reference numbers. As can be seen below, the balls 112, 113 run on raceways designed with different inclinations � and y. More complex routes can also be used, but for safety reasons linear lines are especially advantageous, for example against play or thermal effects. For a given movement or moment of rotation - indicated for example in the lower part of figure 16 by means of an adjustment path V in front of the device in the upper part of figure 16 - these raceways respectively produce an elevation H1 and H2 and as a result a total elevation G. The stop limits the elevation H1 and therefore the total elevation G does not depend linearly on the adjustment travel V.

The raceways can be designed, for example, to result in the characteristic curves represented

25 in Figures 17 and 18. The characteristic curve represented in Figure 19 is the result of the parallel connection with respect to the turning moment, since the parallel connection with respect to the turning moment sum the moments and with the serial connection With respect to the axial clamping force, the clamping force of both units is identical. When flank 123 is reached, the external clamping unit 111 simply contributes with its characteristic curve to the overall characteristic curve.

Figures 20 to 21 show another form of characteristic curve, so that with the negative slope in the internal tightening unit, an especially desired global characteristic curve is obtained (figure 22).

As can be seen immediately in Figures 17 to 22, the clamping units of the present examples of

35 execution show a characteristic curve of work regime-tightening force or turning moment-tightening force with a practically constant slope. Despite these practically constant slopes, the use of two clamping units allows to obtain a characteristic curve adapted to the corresponding requirements. Among other things, this is possible because both clamping units 110, 111 respectively make a first contribution to the clamping force with a first turning moment and a second contribution to the clamping force with a second turning moment, and the difference between the first and the second contribution of the first clamping unit 110 diverges from the difference between the first and the second contribution of the second clamping unit 111.

In general, friction transmissions work at a certain interval with respect to the different types of work regime. In general it is required that at the lower end of this range there is a certain clamping force and at the upper end thereof there is a greater clamping force. To avoid problems with possible tolerances, it may be convenient to provide a constant slope of the characteristic work-force-tightening curve between these two points in the operating range. Under these conditions, for example, the characteristic curve shown in Figure 23 can be implemented with a clamping mechanism consisting of a single unit, even if the operating range is only between 50 Nm and 350 Nm. However, as a consequence, a considerable basic load remains in the system that significantly reduces performance. This can be avoided, for example, so that the characteristic curve has a variable slope such as that shown in Figure 24. In this case the characteristic curve preferably has an almost constant slope in the operating area between 50 Nm and 350 Nm and below it the clamping force falls to about 0 N, specifically under 1 N, in the resting state (0 Nm). This reduces the basic load considerably

55 throughout the system and can increase overall performance. However, a characteristic curve with a variable slope in a clamping unit entails tolerance problems, which avoids the present invention by using at least two clamping units, as already mentioned.

The present invention preferably proposes that the characteristic work-force-tightening curve, such as that represented specifically in figures 24 and 25, has a somewhat smaller average slope in an operating area (see 50 Nm to 350 Nm in the figure 24 or 25) that below this area. Thus, the basic load of the entire system can be lowered and therefore the performance increases. On the other hand, it is also possible to think of devices that have a desirable characteristic curve, analogous to that of Figure 19, in an operating area between 100 Nm and 350 Nm. A characteristic curve like this can also be achieved, over

65 everything, with two tightening units and a lower sensitivity to tolerances.

In addition, to minimize losses throughout the system, it may be convenient to reduce the clamping force depending on a second working regime, especially, for example, of the total load or of an input turning moment, as shown, for example, in figure 25. In this way, the performance of the entire system can be increased.

5 The latter can be guaranteed, for example, with the device shown in Figure 26, which essentially corresponds to the device shown in Figures 28 and 29, although here the cones 101 and 102, apart from a bearing on cylindrical roller bearings 106 , are axially supported by angular contact ball bearings 124.

10 In this exemplary embodiment, the clamping mechanism is also formed by two units 125, 126, but unlike the device according to figures 28 and 29 the unit 125 is placed in the outlet cone 102 and the unit 126 in the cone of input 101. In this way, the entire clamping mechanism can determine both the moment of rotation of the entrance and the moment of rotation of the exit and convert it into a force of tightening. The clamping units 125, 126 have the characteristic curves shown in Figures 27 and 28. Hence the characteristic curve.

15 shown in Figure 29, which fundamentally corresponds to the characteristic curve of the output clamping unit 125, but which for low turning moments is transformed into a horizontal line. The slope of the characteristic curve of the output clamping unit 125 is chosen such that this curve cuts the ideal characteristic curve of full load in the operating range, so that at high output rotation moments a sufficient tightening force. In addition the complete device is designed so that at full load it does not

20 falls below said ideal characteristic curve, even in the lower speed zone. In the case of partial loads and depending on them, it may fall below the ideal characteristic curve of full load, which reduces the total system load even more, although in fact it provides too high clamping forces when it works. at full load. By selecting the slope of the characteristic curve of the output clamping unit 125, its cut-off point can be moved with the ideal characteristic curve at full load for

25 to minimize total losses. As can be seen directly in Figure 29, the slope of the characteristic curve of the output clamping unit 125 cannot be chosen equal to the slope of the ideal characteristic curve of full load in the operating range, because then they do not take place the effects of the second clamping unit 126.

The latter is also possible by coupling both clamping units 125, 126, as shown in the examples of Figures 30 and 31. These devices essentially correspond to those in Figures 28 and 29 or 26, where the components They have identical reference numbers of the same function.

In these embodiments, the clamping units 125, 126 are respectively located in different members of

The friction transmission, as is also the case of the embodiment according to Figure 26. In this case, the clamping units 125, 126 respectively include ball devices 127, 128 respectively supported on the clamping discs 129, 130 of the input shaft 104 and output shaft 105. On the other hand, the balls 128 rest on a pressure plate 131 that can move in the axial direction, but which rotates in solidarity with the input cone 101. This pressure plate serves the same piston time for hydraulic feedback 132, with a

40 piston 133 which in turn is attached to the pressure plate 130. On the outlet side of the clamping unit 125 there is no other pressure plate provided, since otherwise the balls 127 are directly next to the conical group output 102. In this regard, a separate pressure plate can also be provided for recording the corresponding characteristic curves.

45 The hydraulic feedback 132 is directed through through tubes 134, 135 into the cone 101, 102. Instead of this hydraulic feedback 132 a mechanical system 135 can also be provided as the device of Figure 31, which interacts with the corresponding plates 136, 137 of the clamping units 125, 126.

This coupling allows you to choose exactly for the characteristic curve of the output clamping unit 125 the

50 slope of the ideal characteristic curve in the operating range (see, for example, figure 25). Then this characteristic curve is raised to the desired height with the input clamping unit 126. At small loads a corresponding decrease is produced depending on them, so that the entire device basically follows the ideal characteristic curve of Figure 25, as can be seen in figure 34.

Claims (27)

1. Transmission of cone and friction ring, with an entrance cone, an exit cone and a friction ring that surrounds one of the cones, as members (1, 2, 3) that rotate one on the other transmitting a moment of turn, and with 5 a clamping mechanism for pressing said members (1, 2, 3), with means to capture a relevant magnitude, such as in particular the moment of rotation transmitted, and with means to apply a clamping force corresponding to one of the captured quantities , characterized in that the tightening mechanism comprises at least two partial tightening mechanisms (9, 10, 11; 14), the first of which has a shorter response time than the second. 2. Transmission of cone and friction ring according to claim 1, characterized in that the first partial tightening mechanism (9, 10, 11) is not regulated. 3. Transmission of cone and friction ring according to claim 1 or 2, characterized in that the second partial tightening mechanism (14) is regulated. 4. Transmission of cone and friction ring, with an entrance cone, an exit cone and a friction ring that surrounds one of the cones, as members (1, 2, 3) that rotate one on the other transmitting a moment of rotation, and with a clamping mechanism to press said members (1, 2, 3), with means to capture a relevant magnitude, 20 as in particular the moment of rotation transmitted, and with means to apply a clamping force corresponding to one of the magnitudes captured, characterized in that the clamping mechanism comprises at least two partial clamping mechanisms (9, 10, 11; 14) and the first partial clamping mechanism (9, 10, 11) provides a clamping force greater than or equal to that provided by the complete device and the second partial clamping mechanism

(14)

 reduces the clamping force provided by the first partial clamping mechanism (9, 10, 11). 25

5. Cone and friction ring transmission according to one of claims 1 to 4, characterized in that the second partial clamping mechanism (14) applies a force opposite to that provided by the first partial clamping mechanism (9, 10, 11) .

Transmission of a cone and friction ring according to one of claims 1 to 5, characterized in that the second partial clamping mechanism (14) partially compensates for the force exerted by the first partial clamping mechanism (9, 10, 11) .

Transmission according to one of claims 1 to 6, characterized in that the second partial clamping mechanism (14) is hydraulically actuated. 8. Transmission according to claim 7, characterized in that the hydraulic regulation includes an electromagnetically actuated piston (48). Transmission according to claim 8, characterized in that in its compression path the piston first closes an overflow / filling hole (52). 10. Transmission according to claim 7, characterized in that the hydraulic regulation includes a pump gears (61). Four. Five

eleven.

Transmission according to claim 10, characterized in that the gear pump is driven by an electric motor (62) that applies a turning moment as a function of the current.

12.

Transmission according to one of claims 1 to 11, with at least two work regimes, where

50 minus one input element (101) and at least one output element (102) are pressed together by at least one clamping mechanism whose force varies depending on the respective working regime, characterized in that the clamping mechanism (108; 125, 126) consists of at least two units (110, 111; 125, 126). 13. Transmission according to one of claims 1 to 12, characterized in that both clamping units (110, 55 111; 125, 126) have different characteristic curves of work-tightening force. 14. Transmission according to one of claims 1 to 13, characterized in that both clamping units (110, 111; 125, 126) respectively make a first contribution to the clamping force in the first working regime and a second contribution to the force of tightening in the second work regime, and because the difference 60 between the first and the second contribution of the first clamping unit diverges from the difference between the first and the second contribution of the second clamping unit. 15. Transmission according to one of claims 1 to 14, characterized in that both clamping units are configured to act in parallel as regards the determination of the working regime and / or the clamping force. 65 16. Transmission according to one of claims 1 to 15, characterized in that both clamping units (110, 111; 125, 126) are configured to act in series as regards the determination of the working regime and / or the clamping force . Transmission according to one of claims 1 to 16, characterized in that at least one clamping unit (110, 111; 125, 126) has a characteristic work-force clamping curve with a practically constant slope.

18.

Transmission according to one of claims 1 to 17, characterized in that the clamping mechanism (108; 10 125, 126) comprises at least two units coupled to each other (110, 111; 125, 126).

19. Transmission according to claim 18, characterized in that the coupling is of the mechanical type.

twenty.

Transmission according to claim 18 or 19, characterized in that the coupling is hydrodynamic or hydrostatic.

21. Transmission according to one of claims 1 to 20, characterized in that a clamping unit (126) is located on the inlet side and a clamping unit (125) is located on the outlet side. 22. Transmission according to one of claims 1 to 21, with at least two working regimes, in which at least one input element (101) and at least one output element (102) are mutually pressed by at least one clamping mechanism (108; 125, 126) with a variable clamping force depending on the corresponding working regime, characterized in that the clamping mechanism has a characteristic curve of working regime-clamping force whose average slope between a resting state of friction transmission and a first The work regime is different than between the first work regime and a second work regime. 23. Method of operation of a cone and friction ring transmission with at least one inlet cone (101) and at least one outlet cone (102) that are mutually pressed by a clamping mechanism (108; 125, 126) , characterized in that the clamping mechanism (108; 125, 126) is actuated by a characteristic curve of 30 work regime-tightening force whose average slope between a state of rest of the friction transmission and a first work regime is different than between the first work regime and a second one. 24. Method and transmission of friction according to one of claims 1 to 23, characterized in that the speed of work is chosen proportionally to the moment of turn of entry and / or exit. 35 25. Method and transmission of friction according to one of claims 1 to 24, characterized in that the first working regime is the shortest expected moment of rotation at full load. 26. Friction method and transmission according to one of claims 1 to 25, characterized in that the second working regime is the greatest expected moment of rotation at full load. 27. Friction method and transmission according to one of claims 1 to 26, characterized in that it has at least two clamping units (125, 126) that respectively exert a variable force based on several work regimes, such as the moment Incoming turn, the outbound turning moment, the total load, 45 power or similar. 28. The method and transmission of friction according to one of claims 1 to 27, characterized in that the clamping mechanism (108; 125, 126) has a characteristic turning moment-tightening force curve in which the disappearance of the turning moment produces a clamping force drop of approximately 0 N, about 50 all below 1N. 29. Friction method and transmission according to one of claims 1 to 28, characterized in that the clamping mechanism (108; 125, 126) has a characteristic turning moment-tightening curve that runs at full load, between a lower turning moment and a higher expected turning moment, it has a 55 average slope less than below the lowest expected turning moment in progress. 30. Method and transmission of friction according to one of claims 1 to 29, characterized in that the clamping mechanism (125, 126) has a characteristic work-force-tightening curve that depends on the load. 31. Friction method and transmission according to claim 30, characterized in that the clamping force is lower for loads less than full load.