WO2002025134A1

WO2002025134A1 - Device and method for modifying the speed of a shaft

Info

Publication number: WO2002025134A1
Application number: PCT/DE2001/002780
Authority: WO
Inventors: Marcus Schulz
Original assignee: Robert Bosch Gmbh
Priority date: 2000-09-18
Filing date: 2001-07-21
Publication date: 2002-03-28
Also published as: EP1322870A1; DE10194007D2; DE10046035A1; AU2001278397A1

Abstract

The invention relates to a device for modifying the speed of a shaft (10), comprising at least one forced action element (12), which can have a different angular velocity from that of the shaft (10) and at least one contact element (14) for producing a contact between the shaft (10) and the forced action element (12). The contact between the forced action element (12) and the contact element (14) is dependent on the torque of the shaft (10). The invention also relates to a method which can be advantageously implemented using the inventive device.

Description

Device and method for changing the speed of a shaft

The invention relates to a device for changing the rotational speed of a shaft with at least one constraining means, which can have an angular velocity that is different from the angular velocity of the shaft, and at least one contact means for establishing contact between the shaft and the constraining means. The invention further relates to a method for changing the rotational speed of a shaft, in which a contact is used to make contact between the shaft and a constraining means, which contact can have an angular speed that is different from the angular speed of the shaft.

State of the art

With generic systems, the rotation of a shaft can be blocked or braked and released again. These functions can be implemented by a wide variety of clutches, for example in friction clutches, dog clutches or magnetic clutches. A locked or braked state is achieved when the clutch is closed or closing, the clutch being the connecting rotating shaft with a generally spatially fixed part. , The shaft is released by opening the clutch so as to their ^'axis rotate. Systems of the generic type are likewise known which are designed as a brake, for example as a band brake. The systems of the prior art have in common that they are actively actuated by a signal from the outside. In the case of a conventional clutch of a motor vehicle manual transmission, this active signal conveyed from the outside consists, for example, of depressing or releasing the clutch pedal. For the actuation of the generic devices, separate device components are therefore required, by means of which the arrangement as a whole is complex.

Advantages of the invention

The invention is based on the generic device in that the contact between the constraining means and the contact means depends on a torque of the shaft. There is therefore no need for any active elements which influence the contact between the constraining means and the contact means and thus the speed of the shaft from the outside. Rather, a torque of the shaft, which is naturally available during a rotational movement, is used to influence the rotational speed of the shaft, that is to say to lock or brake the shaft, for example.

The contact between the constraining means and the contact means preferably depends on the magnitude of the torque. It it is therefore possible to allow an uninfluenced rotation of the shaft in a certain value range of the torque, while the speed of the shaft is influenced in another value range of the torque.

It is also advantageous if the contact between the constraining means and the contact means depends on the direction of the torque of the shaft. Consequently, it can be achieved that the shaft rotates freely in one direction, while rotation in the other direction and a related torque reversal influence the rotational speed of the shaft, for example by locking the shaft.

It is particularly preferred if the constraining means is fixed in space. A device is thus available in which the shaft is blocked or braked by contact of the contact means with the fixed space constraining means, ^■ so that overall a purely passive reduction in the speed of a shaft is possible.

The device according to the invention is particularly advantageous in that at least one driver is arranged on the shaft, that the contact means has a radially displaceable contact element, that a force dependent on the torque of the shaft can be applied to the contact means by the driver, and that the contact element is dependent on the force dependent on the torque of the shaft changes its radial position. The driver, which is arranged on the shaft, serves to transmit the torque to the contact means, so that the Konüaktmittεl depending on this torque can make contact with the constraining means. This takes place in an advantageous manner in that a contact element of the contact means is shifted in its radial position so that it can come into contact with a radially external constraining means.

It is particularly preferred if the contact means comprises a knee lifting mechanism. By bending or stretching the knee joint of the knee lifting mechanism, the radial position of the contact element, which is attached, for example, to one end of the knee lifting mechanism, can be changed. The knee joint is preferably flexed or stretched under the influence of an elastic restoring force.

The device is particularly advantageous in that several drivers are provided on the shaft, that several contact means are provided on a rotatable inner ring, and that the axis of rotation of the shaft coincides with the axis of rotation of the inner ring. In this way, the resulting forces are evenly distributed on the shaft. Furthermore, ^* several contact means are available, so that a lower force when locking or braking the shaft has to be absorbed per contact means.

The device is particularly advantageous in that the coercive means can cooperate with the contact means by closing. In this way, a reliable locking of the shaft is made possible. In this context, it is particularly advantageous if the constraining means is realized by a ring with an undulating inner profile and if the contact element is a pawl which can be snapped into the undulating inner profile. By extending the pawl in the radial direction, it can latch into a trough of the undulating inner profile, so that a reliable positive locking connection is created.

It is of particular advantage if the contact element changes its radial position dynamically up to an upper limit torque of the shaft in a first direction of the torque, and if the upper limit torque of the shaft exceeds the contact element changes its position abruptly to a contact position and with the constraining means cooperates and the contact element maintains its contact position when the shaft falls below the upper limit torque. The shaft can therefore rotate unaffected by the constraining means until the upper limit torque is reached. Only when the upper limit torque is exceeded does the interaction between the contact means and the constraining means occur, so that the shaft is blocked. This sudden switching is also referred to as "snap-through behavior". After the sudden switching, the contact means reaches a stable position, so that the contact element maintains its contact position even if the torque is reduced as desired, that is to say in particular if the upper limit torque is undershot. In a second direction of the torque of the shaft, which is opposite to the first direction of the torque of the shaft, the contact element can preferably be guided out of its contact position. When the torque is reversed, the drivers of the shaft can thus cause the contact means to give up their position locked with the constraining means, so that the rotation of the shaft is released again.

In another preferred embodiment, the constraining means can interact with the contact means by frictional force. There is therefore no need to completely lock the shaft rotation. Rather, the friction can also gradually reduce the rotational speed.

In this context, it is particularly advantageous if the constraining means can interact with the contact means by frictional engagement. The frictional force can thus be increased to such an extent that the shaft rotation can also be completely locked.

This can be achieved particularly effectively in that the constraining means is realized by a ring with an essentially smooth inside and in that the contact element is a brake shoe which can interact with the inside of the ring. The braking force can thus be gradually increased by radially displacing the brake shoes of the contact means. If the brake shoes are part of a knee lifting mechanism in this case, this is designed so that that the toggle lever mechanisms cannot penetrate even with maximum braking forces.

The invention shows its particular advantages in that the shaft is the ring gear shaft of a planetary gear, that the crankshaft of an engine is connected to the planet gear carrier, that the sun gear shaft of the planetary gear carries a pulley, and that a sprag clutch is integrated between the sun gear shaft and the ring gear shaft. With such a construction, three different operating conditions can advantageously be generated with a combination of internal combustion engine and starter-generator. First, the internal combustion engine can be started with a large gear ratio between the crankshaft and the starter generator, which drives a belt pulley via a belt drive. Secondly, generator operation with a low gear ratio can take place between the crankshaft and the starter generator. Third, stationary air conditioning is possible in which the pulley is uncoupled from the crankshaft. In this connection, the device is have advantageous that locks with the crankshaft as the drive of the sprag and the forcing means no influence on the ring gear shaft especially as ^¬. In this Be ^¬ the planetary gear drive blocked, and crankshaft pulley and gear rotate at the same speed. The starter generator works in generator mode.

However, it can also be advantageous that the sprag freewheel is free with the pulley as the drive Force means up to an upper limit torque of the ring gear shaft have no influence on the ring gear shaft and the force means from an upper limit torque of the ring gear shaft have an influence on the ring gear shaft. In this way, the system can be used for air conditioning in a stand. By keeping the torque of the ring gear shaft small enough, the starter generator can always be used to operate a compressor for an air conditioning system when the crankshaft is stationary. However, in this embodiment, the arrangement can also be used to start the internal combustion engine, namely by increasing the torque of the ring gear shaft, so that it applies a torque above the upper limit torque. Due to the presence of a torque above the upper limit torque, the ring gear shaft is braked or locked, and consequently the power of the starter generator is transmitted to the crankshaft of the internal combustion engine via the pulley so that it starts,

The invention builds on the generic method in that the contact is established between the constraining means and the contact means as a function of a torque of the shaft. No active elements are therefore required which influence the contact between the coercive means and the contact means and thus the speed of the shaft from the outside. Rather, a torque of the shaft, which is naturally available during a rotational movement, is used to influence the rotational speed of the shaft, that is to say to lock or brake the shaft, for example. The contact between the constraining means and the contact means is preferably established as a function of the magnitude of the torque. It is therefore possible to allow an uninfluenced rotation of the shaft in a certain value range of the torque, while the speed of the shaft is influenced in another value range of the torque.

It is also advantageous if the contact between the constraining means and the contact means is established as a function of the direction of the torque. Consequently, it can be achieved that the shaft rotates freely in one direction, while rotation in the other direction and a related torque reversal influence the rotational speed of the shaft, for example by locking the shaft.

In a particularly preferred embodiment, the constraining means is spatially fixed. Thus, a method is available, in which the shaft by contact ^'of the contact means will be locked with the spatially fixed coercion or braked, so that is possible for a total shaft a purely passive reduction of the speed.

The method is particularly advantageous if at least one driver is arranged on the shaft, if the contact means has a radially displaceable contact element, if a force dependent on the torque of the shaft is applied to the contact means by the driver and if the contact element is a function of the radial force dependent on the torque of the shaft Position changed. In this embodiment of the method, the driver, which is arranged on the shaft, serves to transmit the torque to the contact means, so that the contact means can make contact with the constraining means as a function of this torque. This takes place in an advantageous manner in that a contact element of the contact means is displaced in its radial position, so that it can come into contact with a radially outer constraining means.

It is advantageous if the constraining means interacts with the contact means by positive locking. In this way, a reliable blocking of the shaft is made possible.

In this context, it is advantageous if the constraining means is realized by a ring with an undulating inner profile and if the contact element is a pawl which engages in the undulating inner profile. By extending the pawl in the radial direction, it can latch into a trough of the undulating inner profile, so that a reliable positive locking connection is created.

It is particularly advantageous if the contact element dynamically changes its radial position up to an upper limit torque of the shaft in a first direction of the torque, and if the upper limit torque of the shaft is exceeded, the contact element suddenly changes its radial position to a contact position and with it Coercive agents work together and exceed the upper limit torque of the shaft, the contact element maintains its contact position. Until the upper limit torque is reached, the shaft can therefore rotate unaffected by the constraining means. Only when the upper limit torque is exceeded does the interaction between the contact means and the constraining means occur, so that the shaft is locked. This sudden switching is also referred to as "snap-through behavior". After the sudden switching, the contact means reaches a stable position, so that the contact element maintains its contact position even if the torque is reduced as desired, that is to say in particular if the upper limit torque is undershot. Any mechanisms with "snap-through behavior" can advantageously be used in the context of the invention.

In the case of a second direction of the torque of the shaft, which is opposite to the first direction of the torque of the shaft, the contact element is preferably guided out of its contact position. When the torque is reversed, the drivers of the shaft can thus cause the contact means to give up their position locked with the constraining means, so that the rotation of the shaft is released again.

In a further preferred embodiment of the method, the constraining means cooperates with the contact means by frictional force. There is therefore no need to completely lock the shaft rotation. Rather, the friction can also gradually reduce the rotational speed. It is particularly preferred if the constraining means interacts with the contact means by frictional engagement. The frictional force can thus be increased to such an extent that the shaft rotation can also be completely locked.

It is advantageous if the constraining means is realized by a ring with an essentially smooth inside and if the contact element is a brake shoe which is braked by the inside of the ring. The braking force can be gradually increased by radially displacing the brake shoes of the contact means. In this case, if the brake shoes are part of a knee lifting mechanism, this is designed so that the knee lever mechanisms cannot penetrate even with the maximum braking force.

The method of the invention ^is' particularly when the shaft is the ring gear of a planetary gear, when the crankshaft of an engine is connected to the gear rack when the sun gear of the planetary gear carries a pulley and when a sprag clutch is integrated between the sun gear and ring gear. With such a construction, three different operating states can advantageously be generated with a combination of an internal combustion engine and a starter-generator. First, the internal combustion engine can be started with a large gear ratio between the crankshaft and the starter generator, which drives a belt pulley via a belt drive. Secondly, generator operation with a low gear ratio can take place between the crankshaft and the starter generator. Third, stationary air conditioning is possible in which the pulley is uncoupled from the crankshaft.

Then it is particularly advantageous if the clamping body freewheel locks with the crankshaft as the drive and the constraining means have no influence on the ring gear shaft. In this mode, the planetary gear is locked and the crankshaft, pulley and ring gear rotate at the same speed. The starter generator works in generator mode.

On the other hand, it is advantageous if with the belt pulley as the drive the sprag freewheel is free, the constraining means have no influence on the ring gear shaft up to an upper limit torque of the ring gear shaft and the constraining means have an influence on the ring gear shaft from an upper limit torque of the ring gear shaft. In this way, the system can be used for air conditioning in a stand. By keeping the torque of the ring gear shaft small enough, the starter generator can always be used to operate a compressor for an air conditioning system when the crankshaft is stationary. However, in this embodiment, the arrangement can also be used to start the internal combustion engine, namely by increasing the torque of the ring gear shaft, so that it applies a torque above the upper limit torque. Due to the presence of a torque above the upper limit torque, the ring gear shaft is braked or locked, and consequently the force of the starter generator is transmitted via the belt disc is transferred to the crankshaft of the internal combustion engine so that it starts.

The invention is based on the surprising finding that a passively switching locking element or braking element can be made available by using the torque of the shaft to be locked or braked as a controlling variable. By means of a suitable arrangement of the device according to the invention for the interaction with a planetary gear, an internal combustion engine start with a large gear ratio, generator operation with a low gear ratio and stationary air conditioning with a decoupled crankshaft can be implemented in a motor vehicle by passive switching of the device according to the invention.

drawings

The invention will now be explained by way of example with reference to the accompanying drawings using preferred embodiments.

Here ^' shows:

Figure 1 shows a first embodiment of a device according to the invention in a first operating state;

Figure 2 shows the embodiment of Figure 1 in a second operating state; Figure 3 shows the embodiment of Figure 1 in a third operating state;

FIG. 4 shows a second embodiment of a device according to the invention in a first operating state;

FIG. 5 shows the embodiment according to FIG. 4 in a second operating state;

FIG. 6 shows the embodiment according to FIG. 4 in a third operating state;

Figure 7 is an illustration for explaining a contact means;

FIG. 8 shows an illustration to explain a “snap-through behavior”;

FIG. 9 shows a planetary gear transmission in a first operating state;

FIG. 10 shows the planetary gear according to FIG. 9 in a second operating state; and

11 shows the planetary gear according to FIG. 9 in a third operating state.

Description of the design examples

FIG. 1 shows a first embodiment of a device according to the invention in a sectional view. Downtown a shaft 10 is provided in the arrangement. Carriers 16 are arranged on this shaft 10. The axis of the shaft 10 coincides with the axis of an inner ring 40. This inner ring 40 carries contact means 14. Furthermore, stops 38 are arranged on the inner ring, which together with the contact means _. can work. An outer ring 12 with an inner profile 42 is arranged around the inner ring 40. The axis of the outer ring 12 also coincides with the axes of the shaft 10 and the inner ring 40. The outer ring 12 is fixed in space, while the inner ring 40 and the shaft 10 are rotatably mounted. The contact means 14 are each equipped with a knee lifting mechanism 22. This comprises two levers 24, 26 and three joints 28, 30, 32. A spring 56 is arranged between the two joints 28, 32 on the outside. A sliding block 34 is provided on the outer joint 32 of the knee lifting mechanism 22 and is guided in a guide 36. On the outside of the sliding block 34, a pawl 18 is arranged as a contact element. The mode of operation of the toggle lever mechanism 22 is explained in detail below with reference to FIGS. 7 and 8.

Figure 1 shows the device according to the invention in a first operating state. In this operating state, the shaft 10 rotates clockwise. The drivers 16 of the shaft 10 exert a force on the central joints 30 of the toggle lever mechanisms 22, which depends on the torque applied by the shaft 10. The springs 56 are tensioned by the force applied to the toggle lever mechanisms 22. The torque of the shaft 10 has an amount, so that in the state shown, the mass of the knee lifting mechanism is neglected 22 there is a balance of forces between the force applied by the torque and the spring force. Therefore, the inner ring with the shaft 10 can rotate clockwise. In particular, the pawls 18 do not engage in the inner profile of the outer ring 12, so that an unimpeded joint rotation of the shaft 10 and the inner ring 40 can take place.

FIG. 2 shows a second operating state of the device according to FIG. 1. This operating state is achieved in that the shaft 10 exceeds an upper limit torque, which depends on the design of the contact means 14 and the springs 56. If one starts from the state in FIG. 1, the pawl 18 is displaced more and more radially outwards as the torque of the shaft 10 increases. At a certain limit torque, the toggle mechanism 22 strikes through and against the stop 38. This situation is shown in Figure 2. It is also clear that the locking pawl 18 is engaged in the inner profile 42 of the outer ring 12 in this state. Since the outer ring is fixed in space 12, the rotation of the shaft 10 is blocked in the example shown in Figure 2 ^'condition. If the shaft 10 now rotates counterclockwise by a small amount, for example by 20 °, the pawl 18 nevertheless remains in the locked state, since the distance between the stop 38 and the axis of the adjacent spring 56 is chosen to be so large that the spring 56 prevents the knee lifting mechanism 22 from snapping back. On the other hand, the distance between the stop 38 and the axis of the adjacent spring 56 is chosen so small that in the struck state the pawl 18 remains locked in the inner profile 42 of the outer ring 12.

However, if the shaft 10 continues to rotate counterclockwise, the state shown in FIG. 3 is reached at a certain point. Here, the device according to the invention is shown in a third operating state. To clarify the processes, a selection of the toggle lever mechanisms 22 and a selection of the drivers 16 were marked by capital letters in FIGS. 1 to 3. In Figure 1, shaft 10 is in clockwise rotation in contact with toggle mechanism 22A via driver 16A, while shaft 10 is in contact with toggle mechanism 22B via driver 16B. This assignment of driver 16 and knee lifting mechanism 22 does not change in FIG. 2 either. In Figure 3, however, the shaft has rotated counterclockwise, so that, for example, the driver 16A is now in contact with the contact element 22B. Due to the force of the drivers .16 on the respective toggle lever mechanisms 22, these were brought out of their position on the stops 38 according to FIG. The pawls 18 have been moved radially inward, and the shaft 10 can rotate freely with the inner ring 40 counterclockwise.

According to the three movement states shown in FIGS. 1 to 3, the movement of the shaft 10 is blocked asc only if, on the one hand, the torque of the shaft 10 has a certain direction and, on the other hand, it exceeds a certain size. Basically, the drivers 16 and the contact means 14 are arranged such that the drivers 16 can come into contact with adjacent toggle lever mechanisms 22 from both sides. However, the construction is carried out in such a way that there are no other possible collisions between the drivers and any components of the arrangement. In the operating state according to FIG. 2, a positive connection to the inner profile 42 of the outer ring 12 is established via the pawls 18. During the transition from the operating state according to FIG. 2 to the operating state according to FIG. 3, the shaft 10 initially runs freely without a driver 16 interacting with the inner ring 40. After a while, for example, the driver 16A then comes into contact with the knee lifting mechanism 22B. Up to this point in time, a freewheel has been implemented when the torque is reversed. For example, if the force on the joint 30 of the knee lifting mechanism 22B by the driver 16A is large enough, the knee lever mechanisms snap back and the pawls 18 release the inner ring 40. The magnitude of the force required for the toggle mechanisms 22 to snap back depends on the position of the stops 38. The force can be chosen arbitrarily small depending on the amount. In this context, reference is made to the following publication: Schulz, M. and Pellegrino, S. (2000), Ξguilibrium paths of mechanical systems with unilateral constraints, part I: theory, to apear in: The Royal Society Proceedings: Mathematical, Physical and Engineering Sciences. Here, a theory about equilibrium paths of systems with one-sided bonds is derived.

It should also be noted in principle that the diameters of the inner ring 40 and the outer ring 12 are smaller. can be selected if the drivers 16 are aligned axially rather than radially. In this way, an overall more compact arrangement can be achieved.

Figure 4 shows a second embodiment of a device according to the invention in a sectional view. This embodiment is similar in many details to the embodiment according to FIGS. 1 to 3. In contrast to the embodiment according to FIGS. 1 to 3, in the embodiment according to FIG. 4 the contact elements on the contact means 14 are designed here as brake shoes 20. In contrast to the embodiment according to FIGS. 1 to 3, the outer ring 12 in the embodiment according to FIG. 4 has an essentially smooth inside.

FIG. 4 shows a first operating state in which the shaft 10 exerts a comparatively low torque on the central joints 30 of the toggle lever mechanisms 22. Consequently, the force of the springs 56 is sufficient to prevent the brake shoes from contacting the inside of the outer ring 12.

However, if the torque of the shaft 10 increases, the operating state shown in FIG. 5 occurs, in which the brake shoes 20 are braked from the inside of the outer ring 20. If the shaft 10 has sufficient torque, the braking force can be so great that the shaft 10 is completely prevented from rotating by frictional engagement. In contrast to the first embodiment according to FIGS. 1 to 3, the system is designed in such a way that the toggle lever mechanisms 22 cannot penetrate even when the maximum forces occur. Farther solve at torque reversal of the shaft 10 in contrast to the execution orm according to the figures. 1 to 3, the brake shoes 20 immediately from the inside of the outer ring 12. The shaft 10 initially runs freely. The drivers 16 then reach the middle joint 30 of the toggle lever mechanisms 22. When the shaft 10 rotates further counterclockwise, the operating state shown in FIG. 6 is assumed, and the shaft 10 can move the inner ring via the drivers 16 and the middle joints 30 of the toggle lever mechanisms 22 40 also cause it to rotate counterclockwise.

In the embodiment according to FIGS. 4 to 6, too, certain toggle lever mechanisms and certain drivers are identified by capital letters. In FIGS. 4 and 5, the driver 16A is connected to the knee lifting mechanism 22A, while, for example, the driver 16B is connected to the knee lifting mechanism 22B. When the shaft 10 rotates counterclockwise, as shown in FIG ^. 6, the driver 16A is connected to the knee lifting mechanism 22B, for example.

Also related to. 4 to 6 it should be noted in principle that the diameters of the inner ring 40 and the outer ring 12 can be selected to be smaller if the drivers 16 are directed axially rather than radially.

FIG. 7 serves to explain the contact means 14 in more detail. The contact means, which form a knee lifting mechanism 22, comprise two levers 24, 26, each of which has a ne length L. The levers are connected to one another via a joint 30. Further joints 28, 32 are arranged on the ends of the levers 24, 26 facing away from the connection point. These joints 28, 32 are connected to a linearly elastic spring 56, which has a spring constant c. The left lever 24 is fixed in space via the joint 25. The right lever 26 is horizontally displaceably mounted on a sliding block 34 via a further joint 32. The joints 28, 30, 32 are preferably designed as cylindrical joints, the axes of which are all parallel and perpendicular to the plane of representation. The entire knee lifting mechanism 22 moves in the representation plane with a degree of freedom of 1.

The angular coordinate φ is shown to illustrate the possibilities of movement of the knee lifting mechanism. With spring 56 not deformed, let φ = φo. A certain equilibrium position of the system is established under the action of a vertically directed force F.

3 shows the equilibrium positions φ as a function of a control parameter Λ. The control parameter Λ corresponds to the force F scaled by the factor 4cL, i.e. Λ = F / 4cL. The graph in FIG. 8 is also called the equilibrium path, since all points of the curve correspond to equilibrium positions of the mechanism, in each case for different angles φ. The course of the equilibrium path is shown qualitatively in FIG. Points of the thickly drawn curves correspond to stable equilibrium positions, and points of the thinly drawn curve correspond to unstable equilibrium positions. The points with horizontal tangents A and B are also unstable and are called limit points. For example, a method for computing equilibrium paths of mechanical systems is discussed in the following publication: Thompson, JMT and Hunt, GW ('1973), A general theory of elastic stability, J. Wiley, London.

The behavior of the system can be described if the force in a model is increased quasi-statically from zero. At the beginning, at F = 0, the system is in the stable equilibrium position φo. With F growing quasi-statically, one moves on the right stable part of the equilibrium path until the limit point A is reached. Here the path becomes unstable. If F is further enlarged, an equilibrium position is no longer reached in the vicinity of the limit point. The mechanism strikes dynamically in the direction of the arrow. This behavior is referred to as "snap-through behavior". The system carries out vibrations. After the vibrations have subsided, the system follows the force from point C upwards from the left part of the stable equilibrium path. The dynamic penetration is associated with a very rapid movement of the cylinder joint 30 from the half-plane above the spring axis into the half-plane below, the spring axis in FIG. 7. This instability phenomenon is used in the embodiments of the invention according to FIGS. 1 to 3 in order to lock the shaft 10 in one direction, specifically when a torque exceeds a critical value. The device is preferably used in connection with a planetary gear, the functioning of which can be seen from FIGS. 9 to 11. The planetary gear is integrated into the device according to the invention such that, for example, a crankshaft is connected to the planet gear carrier 50. A pulley, which is connected to a starter generator via a belt, is connected to the sun gear 54 via the sun gear shaft. A conventional sprag freewheel is integrated between the sun gear shaft and the ring gear shaft connected to the ring gear 48. A ring is located between the ring gear shaft and a spatially fixed constraining means, for example the motor housing _. Connection with the figures 1 to 8 explained mechanism, which the ring gear 48 depending on the size and direction of the acting on the ring gear. Torque locks or releases. To prevent the mechanism from locking due to centrifugal forces alone, a centrifugal lock can be used.

A normal engine operation can be explained with reference to FIG. 9. The crankshaft of the engine drives the planet gear carrier 50 with the planet gears 52 arranged thereon. ^'The sprag between the Sonnenradwel- le and the ring gear is integrated so that in this direction of rotation of the planet carrier blocks 50 of the clamping body freewheel. The contact means, which are arranged between the ring gear shaft and the constraining means, on the other hand, do not lock, since an operating state according to FIGS. 3 or 6 is present. In this operation, the planetary gear is consequently blocked, and sun gear 54, planetary gear Tenradträger 50 and ring gear 4.8 rotate at the same speed.

A further operating state of the planetary gear is shown in FIG. Here the pulley connected to the sun gear 54 acts as a drive; the starter generator consequently provides the drive energy. At a correspondingly low speed, the ring gear 48 rotates counter to the direction of rotation of the sun gear. Because of the low torque of the ring gear and thus the ring gear shaft, operating states according to FIGS. 1 and 4 exist, ie the ring gear shaft and the ring gear are not affected by the interaction of the Contact means and the coercive means blocked. As a result, the energy of the starter generator can be used to drive a compressor of a parking cooler.

If one now increases the speed of the starter generator and thus of the driving sun gear 54, the upper limit torque is exceeded at a certain point. This situation is shown in Figure 11. The ring gear 48 has come to a standstill here due to the blocking of the ring gear shaft. There is an operating state corresponding to FIGS. 2 and 5. The planetary gear carrier 50 can now be rotated by the rotational energy of the sun gear 54 and consequently the internal combustion engine can be started via the crankshaft. In the embodiment according to FIGS. 4 to 6, in which the ring gear 48 is braked by frictional engagement, the Rotation energy of the sun gear, which is present when the vehicle is stationary, is used for the starting process during the transition to starting operation. In this way you get an accelerated internal combustion engine start.

Overall, it is therefore possible to exclusively passive elements solely on the basis ^"of the participating torques between three operating states of an assembly of starter generator and engine switch.

The preceding description of the exemplary embodiments according to the present invention is only for illustrative purposes and not for the purpose of restricting the invention. Various changes and modifications are possible within the scope of the invention without leaving the scope of the invention and its equivalents.

Claims

Expectations

1. Device for changing the speed of a shaft (10) ^' with - at least one forced means (12), which can have a different angular velocity from the angular velocity of the shaft (10), and at least one contact means (14) for establishing contact between the Shaft (10) and the constraining means (12), characterized in that the contact between the constraining means (12) and the contact means (14) depends on a torque of the shaft (10).

2. Device according to claim 1, characterized in that the contact between the constraining means (12) and the contact means (14) depends on the amount of the torque of the shaft (10).

3. Device according to claim 1 or 2, characterized in that the contact between the constraining means (12) and the contact means (14) depends on the direction of the torque of the shaft (10).

4. Device according to one of the preceding claims, characterized in that the constraining means (12) is spatially fixed.

5. Device according to one of the preceding claims, characterized in that at least one driver (16) is arranged on the shaft (10), that the contact means (14) is a radially displaceable

Contact element (18, 20) that one of the driver (16) on the torque of

Shaft (10) dependent force can be applied to the contact means (14) and that the contact element (18, 20) changes its radial position depending on the force dependent on the torque of the shaft (10).

6. Device according to one of the preceding claims, characterized in that the contact means (14) comprises a knee lifting mechanism (22).

7. Device according to one of the preceding claims, characterized in that a plurality of drivers (16) are provided on the shaft (10), that a plurality of contact means (14) are provided on a rotatable inner ring (40) and - that the axis of rotation of the shaft ( 10) coincides with the axis of rotation of the inner ring (40).

8. Device according to one of the preceding claims, characterized in that the constraining means (12) can interact with the contact means (14) by positive locking.

9. Device according to one of the preceding claims, characterized in that the constraining means (12) is realized by a ring with a wavy inner profile (42) and - that the contact element (18) is a pawl which is in the wavy inner profile (42) a ^{¬ can be} locked.

10. Device according to one of the preceding claims, characterized ^• in that the contact element (18) to an upper limit torque of the shaft (10) dynamically changes its radial position in a first direction of the torque of the shaft (10), - on exceeding the upper limit torque of the shaft (10) the contact element (18) suddenly changes its radial position to a contact position and interacts with the constraining means (12) and the contact element (18) maintains its contact position when the upper limit torque of the shaft (10) is undershot.

11. Device according to one of the preceding claims, characterized in that in a second direction of the torque of the shaft (10), which is opposite to the first direction of the torque of the shaft (10), the contact element (18) can be guided from its contact position.

12. Device according to one of the preceding claims, characterized in that the constraining means (12) with the contact means (14) can interact by frictional force.

13. Device according to one of the preceding claims, characterized in that the constraining means (12) can interact with the contact means (14) by frictional engagement.

14. Device according to one of the preceding claims, characterized in that the constraining means (12) is realized by a ring with a substantially smooth inside and that the contact element (20) is a brake shoe which with the inside of the ring (12) in Can interact.

15. Device according to one of the preceding claims, characterized in that the shaft (10) is the ring gear shaft of the ring gear (48) of a planetary gear, that the crankshaft of an engine is connected to the planet gear carrier (50) of the planetary gear, that the sun gear shaft the sun gear (54) of the planetary gear carries a pulley and - that a sprag free wheel is integrated between the sun gear shaft and ring gear shaft (10).

16. Device according to one of the preceding claims, characterized in that with the crankshaft as the drive locks the sprag freewheel and the constraining means (12) have no influence on the ring gear shaft (10).

17. Device according to one of the preceding claims, 5 characterized in that with the pulley as

Drive the sprag freewheel is free, the constraining means (12) up to an upper limit torque of the ring gear shaft (10) have no influence on the 10 ring gear shaft (10) and the constraining means (12) have an influence on the upper limit torque of the ring gear shaft (10) Have ring gear shaft (10).

15 18. A method for changing the speed of a shaft (10), in which a contact between the shaft (10) and a forced means (12) is made by a contact means (14), which is different from the angular velocity of the shaft (10) Have angular velocity

^'Can 20, characterized in that the contact between the urging means (12) and the contact means (14) is produced in response to a torque of the shaft (10).

19. The method according to claim 18, characterized in that the contact between the constraining means (12) and the contact means (14) is produced as a function of the magnitude of the torque of the shaft (10).

20. The method according to claim 18 or 19, characterized in that the contact between the constraining means (12) and the contact means (14) is produced depending on the direction of the torque of the shaft (10).

21. The method according to any one of claims 18 to 20, characterized in that the constraining means (12) is spatially fixed.

22. The method according to any one of claims 18 to 21, characterized in that at least one driver (16) is arranged on the shaft (10), that the contact means (14) is a radially displaceable

Contact element (18, 20) that one of the driver (16) on the torque of

Shaft (10) dependent force is applied to the contact means (14) and that the contact element (18, 20) changes its radial position depending on the force dependent on the torque of the shaft (10).

23. The method according to any one of claims 18 to 22, characterized in that the constraining means (12) cooperates with the contact means (14) by positive locking.

24. The method according to any one of claims 18 to 23, characterized in that the constraining means (12) is realized by a ring with a wave-shaped inner profile (42) and that the contact element (18) is a pawl, which in the wave-shaped inner profile (42 ) engages.

25. The method according to any one of claims 18 to 24, characterized in that in a first direction of the torque of the shaft (10), the contact element (18) dynamically changes its radial position up to an upper limit torque of the shaft (10) , on exceeding the upper limit torque of the shaft (10) the contact element (18), its radial Po ^¬ sition abruptly changed to a contact position and cooperates with the urging means (12) and when it falls below the upper limit torque of the shaft (10) the contact element (18) maintains its contact position.

26. The method according to any one of claims 18 to 25, characterized in that in a second direction of the torque of the shaft (10), which is opposite to the first direction of the torque of the shaft (10), the contact element (13) out of its contact position becomes.

27. The method according to any one of claims 18 to 26, characterized in that the constraining means (12) cooperates with the contact means (14) by frictional force.

28. The method according to any one of claims 18 to 27, characterized in that the constraining means (12) cooperates with the contact means (14) by frictional engagement. ^'

29. The method according to any one of claims 18 to 28, characterized in that the constraining means (12) is realized by a ring with a substantially smooth inside and that the contact element (20) is a brake shoe, which is braked by the inside of the ring (12).

30. The method according to any one of claims 18 to 29, characterized in that the shaft (10) is the ring gear shaft of the ring gear (48) of a planetary gear, that the crankshaft of an engine is connected to the planet gear carrier (50) of the planetary gear that the sun gear shaft of the sun gear (54) of the planetary gear carries a pulley and that a sprag freewheel is integrated between the sun gear shaft and the ring gear shaft (10).

31. The method according to any one of claims 18 to 30, characterized in that the clamping body freewheel blocks and the constraining means (12) have no influence on the ring gear shaft (10).

32. The method according to any one of claims 18 to 31, characterized in that the sprag freewheel is free, - the constraining means (12) up to an upper limit torque of the ring gear shaft (10) have no influence on the ring gear shaft (10) and the constraining means (12) from an upper limit torque of the ring gear shaft (10) have an influence on the ring gear shaft (10).