Patent Application
20080236527
The invention relates to a device for varying the control times of gas exchange valves of an internal combustion engine.
In internal combustion engines, camshafts are used for actuating the gas exchange valves. Camshafts are mounted in the internal combustion engine in such a way that cams attached to them bear against cam followers, for example bucket tappets, drag levers or rocker arms. When the camshaft is set in rotation, the cams roll on the cam followers which in turn actuate the gas exchange valves. Thus, owing to the position and shape of the cams, both the opening duration and amplitude, but also the opening and closing time point of the gas exchange valves are defined.
Modern engine concepts tend toward a variable design of the valve drive. On the one hand, the valve stroke and valve opening duration are to be capable of being configured variably up to the complete cut-off of individual cylinders. For this purpose, concepts, such as switchable cam followers, variable valve drives or electro-hydraulic or electric valve actuations, are provided. Furthermore, it has proved advantageous to be able to exert influence on the opening and closing times for the gas exchange valves while the internal combustion engine is in operation. It is likewise desirable to be able to influence the opening and closing time points of the inlet and outlet valves separately so that, for example, a defined valve overlap can be set in a directed way. By the opening and closing time points of the gas exchange valves being set as a function of the current characteristic map range of the engine, for example of the current rotational speed or the current load, the specific fuel consumption can be lowered, the exhaust gas behavior can be influenced positively and the engine efficiency, maximum torque and maximum power can be increased.
The variability in the gas exchange valve time control, as described, is brought about by means of a relative change in the phase position of the camshaft with respect to the crankshaft. In this case, the camshaft is mostly drive-connected to the crankshaft via a chain, belt or gearwheel mechanism or identically acting drive concepts. Between the chain, belt or gearwheel mechanism driven by the crankshaft and the camshaft is mounted a camshaft adjuster which transmits the torque from the crankshaft to the camshaft. In this case, this device for varying the control times of the internal combustion engine is designed in such a way that, while the internal combustion engine is in operation, the phase position between the crankshaft and camshaft can be maintained reliably, and, if desired, the camshaft can be rotated within a certain angular range with respect to the crankshaft.
In internal combustion engines with a camshaft in each case for the intake and the exhaust valves, these may be equipped in each case with a camshaft adjuster. As a result, the opening and closing times of the intake and exhaust gas exchange valves can be displaced relative to one another in time and the valve time overlaps can be set in a directed way.
The seat of modern camshaft adjuster is generally located at the drive-side end of the camshaft. It consists of a crankshaft-fixed driving wheel, of a camshaft-fixed driven element and of an adjusting mechanism transmitting the torque from the driving wheel to the driven part. The driving wheel may be designed as a chain wheel, belt wheel or gearwheel and is connected fixedly in terms of rotation to the crankshaft by means of a chain, a belt or a gearwheel mechanism. The adjusting mechanism may be operated electromagnetically, hydraulically or pneumatically. It is likewise conceivable to attach the camshaft adjuster to an intermediate shaft or to mount it on a nonrotating component. In this case, the torque is transmitted to the camshafts via further drives.
Electrically operated camshaft adjusters consist of a driving wheel which is drive-connected to the crankshaft of the internal combustion engine, of a driven part which is drive-connected to a camshaft of the internal combustion engine and of an adjusting mechanism. The adjusting mechanism is a three-shaft mechanism with three components rotatable with respect to one another. In this case, the first component of the mechanism is connected fixedly in terms of rotation to the driving wheel and the second component is connected fixedly in terms of rotation to the driven part. The third component is designed, for example, as a toothed component, the rotational speed of which can be regulated via a shaft, for example by means of an electric motor or a braking device.
The torque is transmitted from the crankshaft to the first component and from there to the second component and consequently to the camshaft. This takes place either directly or with the third component being interposed.
By the rotational speed of the third component being suitably regulated, the first component can be rotated with respect to the second component, and consequently the phase position between the camshaft and crankshaft can be varied. Examples of three-shaft mechanisms of this type are inner eccentric mechanisms, double inner eccentric mechanisms, harmonic drives, swashplate mechanisms or the like.
To control the camshaft adjuster, sensors detect the characteristic data of the internal combustion engine, such as, for example, the load state, the rotational speed and the angular positions of the camshaft and crankshaft. These data are fed to an electronic control unit which, after comparing the data with a characteristic map of the internal combustion engine, controls the adjusting motor of the camshaft adjuster.
DE 102 36 507 discloses a device for varying the control times of an internal combustion engine, in which torque transmission from the crankshaft to the camshaft and the adjusting operation are implemented by means of a swashplate mechanism. The device consists essentially of a camshaft wheel, of a camshaft-fixed rotary disk and of a swashplate mechanism. The camshaft wheel is drive-connected to a crankshaft and is produced in one piece with a housing. The swashplate is mounted on an adjusting shaft at a defined angle of incidence and is drive-connected to the housing.
The swashplate and the rotary disk are provided, on their axial side faces in each case facing the other component, in each case with a bevel wheel toothing in the form of a toothed rim. In this case, the swashplate and the rotary disk are arranged in such a way that, because of the mounting of the swashplate on the adjusting shaft at a specific angle of incidence, an angular segment of the toothing of the swashplate engages into an angular segment of the toothing of the rotary disk. There is, in this case, a difference in the number of teeth of the bevel wheel toothings.
The adjusting shaft is drive-connected to a drive unit, for example an electric motor, which drives it at a continuously regulatable rotational speed. A rotation of the adjusting shaft in relation to the rotary disk leads to a wobbling rotation of the swashplate and consequently to a rotation of the engaged angular segment in relation to the rotary disk and to the swashplate. On account of the different number of teeth of the bevel wheel toothings, this leads to a relative rotation of the camshaft with respect to the crankshaft.
If the amount of the relative angle of rotation between the camshaft and crankshaft overshoots a specific value, the internal combustion engine can no longer operate reliably. In the event of an extreme offset, the pistons may knock against the open gas exchange valves, thus leading to engine damage. Phase positions of this kind may occur, for example, due to a failure of the control unit or of the drive of the adjusting shaft or in the case of damage to the device itself. In order to prevent the offset between the angle of rotation of the crankshaft and the angle of rotation of the camshaft from becoming too great, means are provided for limiting the relative angle of rotation of the camshaft with respect to the crankshaft. For this purpose, the rotary disk connected at the camshaft is provided with a clearance, into which a stop arranged on the camshaft wheel engages. The stop may be produced in one piece with the camshaft wheel or be fastened to the latter.
This embodiment has the disadvantage that the stop has to be designed with a very high mass in order to withstand the high forces occurring in the event of a malfunction of the device. This leads to a large mass of the device and to high production costs. Furthermore, this principle proves to be inflexible in terms of the manufacture of various devices having different adjustment angle ranges.
The object on which the invention is based is to provide a device for varying the control times of gas exchange valves of an internal combustion engine with angle-of-rotation limitation, while the mass and the costs of the device are to be reduced. At the same time, high torques are to be capable of being transmitted by the angle-of-rotation limitation. Furthermore, it is to become possible to implement devices having different adjustment angle ranges by means of the same components. This leads to shorter set-up times of the production machines during production and to lower stockkeeping.
In a first embodiment of a device for varying the control times of gas exchange valves of an internal combustion engine, with a driving wheel drive-connected to a crankshaft, and with a swashplate mechanism which has a driven element drive-connected to a camshaft, the object is achieved, according to the invention, in that more than one pairing of a first and of a second boundary wall are provided, a finger being provided for each pairing, each finger engaging between the boundary walls of a pairing, the boundary walls being connected fixedly in terms of rotation either to the driving wheel or to the driven element and the fingers being connected fixedly in terms of rotation to the other component, the boundary walls and the fingers being designed and arranged with respect to one another in such a way that, when a maximum permissible value of the relative phase position of the crankshaft with respect to the camshaft is reached, each finger comes to bear against one of the boundary walls.
In an embodiment of the invention, there is provision for the clearances to be designed identically.
During an operation to adjust the swashplate mechanism, the housing and driving wheel, as components drive-connected to the crankshaft, are rotated in relation to the driven element connected fixedly in terms of rotation to the camshaft. For limiting the angle of rotation, fingers are formed on the driven element, each finger being arranged between two boundary walls. The boundary walls are connected fixedly in terms of rotation to the housing or to the driving wheel. It is likewise conceivable to produce the boundary walls in one piece with the housing or with the driving wheel. A further possibility is to form the fingers on the housing or the driving wheel and to fasten the boundary walls fixedly in terms of rotation to the driven element or to produce them in one piece with the latter.
When a relative rotation takes place between the driven element and the housing or the driving wheel, the fingers travel between the boundary walls in the circumferential direction. The boundary walls and the fingers are designed and mounted with respect to one another in such a way that each of the fingers comes to bear against one of the two respective boundary walls when a maximum permissible relative angle between the camshaft and crankshaft is reached. This prevents a further increase in the relative angle.
By a plurality of fingers being formed, which engage in each case into a clearance, the torques to be transmitted are distributed to a plurality of locations and therefore the forces which a finger has to transmit are minimized, thus leading to lower wear and to an increased service life of the device.
The boundary walls may be formed by clearances which are produced on an inner surface area or outer surface area of a stop disk. The stop disk may be a separately produced component which is fastened fixedly in terms of rotation to the driven element or driving wheel on the device. It is likewise conceivable to produce the stop disk in one piece with the driven element, the driving wheel or the housing.
In a second embodiment of a device for varying the control times of gas exchange valves of an internal combustion engine, with a drive unit drive-connected to a crankshaft and comprising at least one driving wheel, and with a swashplate mechanism which has at least one driven element drive-connected to a camshaft, the object is achieved, according to the invention, in that means limiting the angle of rotation are provided, which limit the relative rotation of the driving wheel with respect to the driven element, angle-of-rotation ranges of different size being capable of being set, during the mounting of the device, by the driven element being oriented with the driving wheel.
For this purpose, the device is provided with a plurality of means limiting the angle of rotation, one group being connected fixedly in terms of rotation to the driven element and a second group being connected fixedly in terms of rotation to the driving wheel or to a component connected fixedly in terms of rotation to the driving wheel. During mounting, the driven element can be mounted in different angular positions with respect to the driving wheel. The means limiting the angle of rotation are formed on the device in such a way that, in any mounting position of the driving wheel with respect to the driven element, other groups of means limiting the angle of rotation can interact. If the adjustment angle range of different groups of means limiting the angle of rotation is designed differently, the desired adjustment angle range can be set, during mounting, by the driving wheel being positioned with respect to the driven element. The same components can therefore be utilized for devices having different angle-of-rotation ranges.
In a first embodiment of this invention, there is provision for a finger and at least two pairings of a first and of a second boundary wall to be provided, the boundary walls being connected fixedly in terms of rotation either to an inner surface area of the drive unit or to an outer surface area of the driven element, and the finger being connected fixedly in terms of rotation to the respective surface area of the other component, the spacings between the boundary walls of various pairings being designed differently, and, in the mounted state of the device, the finger being arranged between the boundary walls of one of the pairings.
The pairings of boundary walls may be implemented, for example, by clearances in a stop disk.
The functioning of this embodiment is similar to the functioning of the first embodiment. Once again, pairings of boundary walls are provided. However, the pairings differ from one another in the spacing of their boundary walls in the circumferential direction. furthermore, the device has arranged on it only one finger which, in the mounted state, engages between the boundary walls of one of the pairings and consequently forms the angle-of-rotation limitation.
The individual components of the device are designed in such a way that, during mounting, the finger can be arranged in any desired clearance. The adjustment angle range of each device can thereby be adapted to the special application, while the same components can be used for various applications. Individualization is carried out, during the mounting of the device, solely by the individual components being mounted in the correct angular relation, with the result that the finger is positioned in the correct clearance.
In a second embodiment of this invention, there is provision for more than one finger and a first and a second boundary wall to be provided, the boundary walls being connected fixedly in terms of rotation either to an inner surface area of the drive unit or to an outer surface area of the driven element, and the fingers being connected fixedly in terms of rotation to the respective surface area of the other component, the width of the fingers being designed differently in the circumferential direction, and, in the mounted state of the device, one of the fingers being arranged between the boundary walls.
This embodiment constitutes a reversal of the first embodiment. A “clearance” is provided which is delimited by the boundary walls. Fingers of different width can be fitted into this “clearance”. The adjustment angle range arises from the width of the “clearance” and the width of the fingers.
In a third embodiment of this invention, there is provision for more than two fingers and a first and a second boundary wall to be provided, the boundary walls being connected fixedly in terms of rotation either to an inner surface area of the drive unit or to an outer surface area of the driven element, and the fingers being connected fixedly in terms of rotation to the respective surface area of the other component, and, in the mounted state of the device, one of the fingers cooperating with the first boundary wall and another of the fingers cooperating with the second boundary wall, in such a way that the adjustment angle range of the device is thereby limited.
The adjustment angle range is in this case limited by two fingers. Each finger limits the rotation of the driving wheel in relation to the driven element in one direction of rotation. If more than two fingers are provided, different permutations as to which finger cooperates with which boundary wall are possible. By virtue of the adapted arrangement of the fingers in the circumferential direction of the device, a plurality of adjustment angle ranges can be implemented by means of the same components.
By the same components being used for different applications, the production costs are lowered, since the same tools can be used, set-up times are avoided and stockkeeping is minimized.
In the embodiments described, the fingers and the clearances may be utilized for calibrating the actual angle value detected by the control. For this purpose, the device is rotated in one direction until the fingers bear reliably in each case against a boundary wall. Subsequently, the camshaft angle sensors are read out, and this value is used as a reference value for operating the internal combustion engine.
Advantageously, the boundary walls are formed by clearances in an inner surface area or outer surface area of a stop disk. The stop disk may be produced as a separately manufactured component and fastened to the device or be produced in one piece with one of its components. By the stop disk being used, the rigidity and consequently the load-bearing capacity of the boundary walls are increased.
In embodiments of the invention, there may be provision for the boundary walls to be produced in one piece with the driving wheel or for the drive unit to contain a housing and for the boundary walls to be produced in one piece with the housing. In this case, there may be provision for producing the finger or fingers in one piece with the driven element.
Alternatively, the boundary walls may be produced in one piece with the driven element, in which case there may additionally be provision for the finger or fingers to be produced in one piece with the driving wheel or for the drive unit to contain a housing and for the finger or fingers to be produced in one piece with the housing.
Further features of the invention may be gathered from the following description and the accompanying drawings which illustrate exemplary embodiments of the invention diagrammatically and in which:
a shows a longitudinal section through a first embodiment according to the invention of a device for varying the control times of gas exchange valves of an internal combustion engine, the device being mounted on a camshaft,
b shows an enlarged illustration of the detail Z marked in
a shows a sixth embodiment according to the invention of a device for varying the control times of gas exchange valves of an internal combustion engine in a first extreme position in a front view,
b shows a sixth embodiment according to the invention of a device for varying the control times of gas exchange valves of an internal combustion engine in a second extreme position in a front view,
c shows a seventh embodiment according to the invention of a device for varying the control times of gas exchange valves of an internal combustion engine in a front view,
d shows an eighth embodiment according to the invention of a device for varying the control times of gas exchange valves of an internal combustion engine in a front view,
An internal combustion engine 100 is outlined in
a, 1b and 2 show an embodiment of a device 1 according to the invention for varying the control times of an internal combustion engine 100. The device 1 comprises, inter alia, a swashplate mechanism 2 comprising a driving bevel wheel 3, of a driven element 4 and of a swashplate 5. A first toothed rim 6 designed as a bevel wheel toothing is formed on one axial side face of the driving bevel wheel 3. Furthermore, a second and a third toothed rim 7, 8 are formed on the axial side faces of the swashplate 5, in this exemplary embodiment the toothed rims 7, 8 likewise being designed in each case as a bevel wheel toothing. In this instance, the second toothed rim 7 is formed on the axial side face, facing the driving bevel wheel 3, of the swashplate 5 and the third toothed rim 8 is formed on the axial side face, facing the driven element 4, of said swashplate 5. The radially outer portion of the driven element 4 is designed as a toothing carrier 9, on the axial side face of which, facing the swashplate 5, a fourth toothed rim 10 is formed. In this embodiment, the fourth toothed rim 10 is likewise designed as a bevel wheel toothing.
The driven element 4 is connected fixedly in terms of rotation to a camshaft 11. In the exemplary embodiment illustrated, the connection between the driven element 4 and camshaft 11 is implemented by means of a first fastening means 12, here a fastening screw 12a. Materially integral, nonpositive, frictional or positive connection methods may likewise be envisaged.
A driving wheel 13 is operatively connected to a primary drive, not illustrated, via which a torque is transmitted from a crankshaft 101 to the driving wheel 13. A primary drive of this type may be, for example, a chain, belt or gearwheel mechanism. The driving wheel 13 is connected fixedly in terms of rotation to a housing 14, and the housing 14 is, in turn, connected fixedly in terms of rotation to the driving bevel wheel 3. In the embodiment illustrated in
The driving bevel wheel 3 and the driven element 4 stand parallel to one another and are spaced apart from one another in the axial direction. Together with the housing 14, the driving bevel wheel 3 and the driven element 4 form an annular cavity 14a in which the swashplate 5 is arranged. By means of first rolling bearings 15, the swashplate 5 is mounted on an adjusting shaft 16 at a defined angle of incidence with respect to the driving bevel wheel 3 and to the driven element 4. The adjusting shaft 16, of essentially pot-shaped design, is provided with a coupling element 17, into which engages a shaft, not illustrated, of a device, likewise not illustrated, by means of which the rotational speed of the adjusting shaft 16 can be regulated. In this embodiment, there is provision for driving the adjusting shaft 16 by means of an electric motor, not illustrated, a shaft, not illustrated, of the electric motor cooperating with the coupling element 17. However, other devices for regulating the rotational speed of the adjusting shaft 16 may also be envisaged. The adjusting shaft 16 is supported via second rolling bearings 18 on a shaft 19a connected fixedly in terms of rotation to the camshaft 11 and designed in the present embodiment as a hollow shaft 19. It is likewise conceivable to mount the adjusting shaft 16 on a screw head of the fastening screw 12a and/or to mount the swashplate 5 on the adjusting shaft 16 by means of a plain bearing.
The swashplate 5 arranged at a defined angle of incidence on the adjusting shaft 16 engages with the second toothed rim 7 into the first toothed rim 6 of the driving bevel wheel 3 and with the third toothed rim 8 into the fourth toothed rim 10 of the driven element 4. In this case, the respective toothed rims 6, 7, 8, 10 are in engagement in each case only in a specific angular range, the size of the angular range being dependent on the angle of incidence of the swashplate 5.
Via the engagement of the toothed rims 6, 7, 8, 10, the torque of the crankshaft 101, transmitted from the primary drive to the driving wheel 13 and from there to the driving bevel wheel 3, is transmitted via the swashplate 5 to the driven element 4 and consequently to the camshaft 11.
If the adjusting shaft 16 is driven by means of an electric motor via a shaft engaging into the coupling element 17, the adjusting shaft 16 is driven at the rotational speed of the driving wheel 13, in order to keep the phase position between the camshaft 11 and crankshaft 101 constant. If the phase position is to be changed, the rotational speed of the adjusting shaft 16 is increased or reduced, depending on whether the camshaft 11 is to lead or lag in relation to the crankshaft 101. Owing to the deviating rotational speed of the adjusting shaft 16, the swashplate 5 executes a wobbling rotation, the angular ranges in which the toothed rims 6, 7, 8, 10 engage one in the other rotating around the swashplate 5, the driving bevel wheel 3 and the driven element 4. In the case of at least one of the pairs of toothed rims, the two toothed rims 6, 7, 8, 10 engaging one in the other have different numbers of teeth. When the angular ranges in which the toothed rims 6, 7, 8, 10 engage one in the other have rotated once around the swashplate 5 completely, this results, on account of the difference in the number of teeth, in an adjustment of the driving bevel wheel 3 with respect to the driven element 4 and consequently of the camshaft 11 in relation to the crankshaft 101. The adjustment angle corresponds to the range occupied by the teeth forming the difference in the number of teeth.
It is conceivable, in this respect, that the toothed rims 6, 7, 8, 10, engaging one in the other, of the two pairs of toothed rims have different numbers of teeth. The adjustment reduction ratio consequently arises from the two resulting reduction ratios.
It is likewise conceivable that the toothed rims 6, 7, 8, 10 of only one pairing of toothed rims have different numbers of teeth. In this case, the reduction ratio arises only from this reduction. In this case, the other pairing of toothed rims serves merely as coupling means with a reduction ratio of 1:1 between the swashplate 5 and the respective component 3, 4.
During the adjustment operation, the driving wheel 13 or the housing 14 rotates with respect to the driven element 4 according to the reduction ratio of the swashplate mechanism 2 and the relative rotational speed of the adjusting shaft 16 with respect to the driving wheel 13. An outer surface area of the driven element 4 is designed as a first radial bearing surface 20. Furthermore, at least part of an inner surface area of the driving wheel 13 or of the housing 14 is designed as a second radial bearing surface 21. The two radial bearing surfaces 20, 21 cooperate as radial bearings 22, with the result that the driving wheel 13 and the housing 14 are mounted rotatably on the driven element 4.
While the internal combustion engine 100 is in operation, the phase position of the camshaft 11 in relation to the crankshaft 101 should be set only within a specific angular range. If higher angles than the maximum permissible extreme values are set, this leads, in the worst case, to the pistons of the internal combustion engine 100 knocking against the open gas exchange valves and to the internal combustion engine 100 consequently becoming inoperative.
These faulty settings of the phase position may be caused, for example, by the failure of the control of the device 1 or by the failure of the drive device or of the device 1 itself. In order to avoid this, means limiting the angle of rotation must be provided, which, in these exceptional cases, prevent a displacement of the phase position beyond predetermined extreme values.
An annular stop disk 23 is fastened to the camshaft-side end of the driving wheel 13. The stop disk 23 may be connected to the driving wheel 13 nonpositively, frictionally, materially integrally or positively. On its radially inner circumferential surface, the stop disk 23 is designed with two clearances 24 extending in the circumferential direction and in the radial direction. In each case a finger 25 produced in one piece with the driven element 4 extends into the clearance 24. The fingers 25, starting from an otherwise circular boundary surface 4a of the driven element 4, extend outward in the radial direction and may be produced with the driven element 4 during the process of forming the latter.
If, while the internal combustion engine 100 is in operation, the phase position between the crankshaft 101 and camshaft 11 is changed by means of the swashplate mechanism 2, the driven element 4 rotates in relation to the driving wheel 13. As a consequence, the driven element 4 is likewise rotated in relation to the stop disk 23 connected fixedly in terms of rotation to the driving wheel 13. The result of this is that the fingers 25 change their position within the clearances 24. In this case, the fingers 25 and the clearances 24 are designed in such a way that the fingers 25 come to bear against one of the two radial boundary walls 26, 27 of the respective clearance 24 when one of the two maximum permissible phase positions of the device 1 is reached. A further change in the phase position to larger angles is consequently prevented and the internal combustion engine 100 is protected from damage.
Furthermore, there is the possibility of integrating further functions into the stop disk 23, such as, for example, the axial mounting of the driving wheel 13 or of the housing 14 with respect to the driven element 4.
Owing to the formation of a plurality of fingers 25, each finger 25 engaging into a clearance 24, the forces acting on the boundary walls 26, 27 and on the fingers 25 are minimized, thus increasing the service life of the device 1.
a and 6b show a sixth embodiment of the invention. In this embodiment, three fingers 25 are formed. Furthermore, three clearances 24 are formed. Each finger 25 engages into a clearance 24. In this case, two clearances 24 are designed as boundary clearances 24a and one is designed as an empty clearance 24b.
a shows the device 1 in a position in which the driven element 4 is in one of its two extreme positions with respect to the driving wheel 13. A finger 25 bears against a boundary wall 26 of the associated boundary clearance 24a, while the other fingers 25 are located within the respective clearance 24.
b shows the device 1 in the second extreme position. In this case, the other finger 25 bears against a boundary wall 27 of the associated boundary clearance 24a, while the other fingers 25 are located within the respective clearance 24.
In this case, two of the fingers 25, in interaction with the respective boundary clearance 24a, are responsible for the adjustment angle limitation, one of the fingers 25 limiting the adjustment angle in one direction of rotation and the other finger 25 limiting the adjustment angle in the other direction of rotation. Owing to the adapted arrangement of the fingers 25 and to the correct positioning of the driven element 4 with respect to the driving wheel 13, different pairs of fingers can assume the adjustment angle limitation function, with different adjustment angle ranges.
As an alternative to the embodiment illustrated, instead of the stop disk being used, noses 23a may be formed on the device, as illustrated in
c shows a seventh embodiment of the invention, the device 1 being illustrated in a front view. The stop disk 23 is in this case provided with two clearances 24. One of the clearances 24 is designed as a boundary clearance 24a shorter in the circumferential direction and the second clearance 24 is designed as an empty clearance 24b longer in the circumferential direction. In this case, three fingers 25 are formed on the driven element 4, the fingers 25 having different widths a, b, c in the circumferential direction. In the mounted state of the device 1, one of the fingers 25 engages into the boundary clearance 24a and the other two fingers 25 into the empty clearance 24b. In this case, the fingers 25 and the boundary clearance 24b are designed in such a way that a defined adjustment angle range is implemented by the interaction of the respective finger 25 with the boundary clearance 24a. In this case, there is provision for designing the length of the empty clearance 24b in the circumferential direction in such a way that the fingers 25 arranged in it do not come to bear against one of its boundary walls 26, 27. During the mounting of the device 1, the driven element 4 can be positioned in three positions in relation to the stop disk 23. In each position, another of the fingers 25 engages into the boundary clearance 24a, as a result of which, in this embodiment, three different adjustment ranges can be set by means of the same parts. In addition, there may be provision for the empty clearance 24b to be designed in such a way and the fingers 25 to be arranged in such a way that, at least in a relative positioning of the driven element 4 with respect to the stop disk 23, in each case one of the fingers 25 positioned in the empty clearance 24b comes to bear against one of its boundary walls 26, 27 when the finger 25 positioned in the boundary clearance 24a comes to bear against a boundary wall 26, 27 of the boundary clearance 24a.
Of course, the embodiments shown in
The operating play of the two bearings is determined solely by the bearing clearance and the reduction in play due to the pressing together of the inner and the outer ring 29, 30 with the adjusting shaft 16 and the swashplate 5 and is lower than 0.1 mm. The spacing between the ball rows is determined by the corresponding spacing of the raceways in the bearing. The axial forces occurring are supported in the bearing itself. Whereas, in the embodiment from
The use of a tapered roller bearing 33, as illustrated in
All the illustrated embodiments of the first rolling bearing 15 may be designed, in general, in an O-, X- and tandem arrangement and with or without a bearing cage 37.
The needle bearings 34 may be fixed by means of spring rings, a pressing together, caulking of the sleeve 34a in the bore, knurling of the sleeve 34a or an adhesive bond.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2004 062 072.5 | Dec 2004 | DE | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP2005/012093 | 11/11/2005 | WO | 00 | 6/12/2007 |
